Electrochemical device

ABSTRACT

An electrochemical device manufactured using an electrode layer in which severe increase of electrode resistance is prevented and/or a solid electrolyte layer in which severe decrease of ion conductivity of a solid electrolyte is prevented is provided. The electrochemical device includes a pair of electrode layers, and a solid electrolyte layer provided between the pair of electrode layers, wherein at least one layer of the electrode layers and the solid electrolyte layer is composed of first particles each providing a function of the at least one layer, second particles and a binder which is composed of an organic polymer and binds the first and second particles, and wherein the at least one layer is formed from a mixture material containing the first particles and binder particles, each of the binder particles including the second particle and the binder carried on at least a part of a surface thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims a priority to Japanese Patent Application No.2007-248279 filed on Sep. 25, 2007 which is hereby expresslyincorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

Several aspects of the present invention relates to an electrochemicaldevice and, more particularly, an electrochemical device having anelectrode layer and/or a solid electrolyte layer formed using binderparticles, each of the binder particles including a particle and abinder carried on at least a part of a surface thereof.

2. Related Art

Along with development of portable equipments such as a personalcomputer and a cellular phone, demand for a small-sized lightweightbattery as a power source of the portable equipments shows a drasticincrease in recent years.

In particular, it is predicted that a lithium battery realizes a highenergy density since lithium has a reduced atomic weight and increasedionization energy. Extensive research has been made in this respect, asa result of which the lithium battery is widely used as a power sourceof the portable equipments these days.

Expansion of a lithium battery market demands a lithium battery having ahigher energy density. In order to comply with such a demand, internalenergy of the lithium battery has been made greater by increasing thequantity of an active material contained in the battery.

Concomitant with this trend, a noticeable increase has been made in thequantity of an organic solvent contained in an electrolyte (anelectrolytic solution) which is a flammable material filled in thebattery. This results in an increased danger of battery firing and,therefore, the problem of battery safety becomes at issue in recentyears.

One of highly effective methods for assuring the safety of a lithiumbattery is to replace the electrolyte containing the organic solventwith a nonflammable solid electrolyte. Among others, use of alithium-ion-conducting inorganic solid electrolyte makes it possible todevelop an all-solid lithium battery that exhibits improved safety.Active research is now being made in this connection.

As an example, S. D. Jones and J. R. Akridge, J. Power Sources, 43-44,505 (1993) discloses an all-solid thin film lithium secondary batteryproduced by sequentially forming a cathode thin film, an electrolytethin film and an anode thin film through the use of a depositionapparatus or a sputtering apparatus. It was reported that the thin filmlithium secondary battery exhibits superior charge-discharge cycleproperties of several thousand cycles or more.

With this thin film lithium secondary battery, however, it is impossiblefor a battery device to retain an electrode active material in a largequantity, thereby making it difficult to obtain a high capacity battery.In order to increase the battery capacity, a great quantity of electrodeactive materials should be contained in an electrode.

For this purpose, electrodes of a bulk type battery are composed of anelectrode mixture material containing electrolyte particles andelectrode active material particles. This makes it possible to maintainan ion-conducting path and an electron-conducting path in theelectrodes, and to obtain a bulk type battery having a high capacity.

The bulk type battery is typically manufactured by compression-moldingthe entire battery device within a mold of a press machine, taking outthe battery device from the mold and placing the battery device into acoin type battery container.

However, in the case of the bulk type battery, particularly, anall-solid lithium secondary battery using a sulfide-basedlithium-ion-conducting solid electrolyte (a sulfide-based lithium-ionconductor), it is known that the capacity thereof is reduced by about 7%from its initial capacity when subjected to several cycles ofcharge-discharge operations at most (see, e.g., DENKI KAGAKU, 66, No. 9(1998)).

Thus, there is currently a demand for development of a bulk typeall-solid lithium secondary battery having improved performance andbeing capable of preventing reduction of a battery capacity over thelapse of charge-discharge cycles.

In the all-solid secondary battery having such a structure, in order toimprove strengths of the electrode layers and the solid electrolytelayer, it is proposed that materials containing a binder composed of anorganic polymer are used as constituent materials thereof (see, e.g.JP-A-07-161346).

In the case of the solid electrolyte layer containing such a binder, itcan be formed by mixing the electrolyte particles with an organicsolvent dissolving the binder therein to obtain an electrolyte paste,applying the electrolyte paste onto a substrate, and then drying thesame.

In the case of the electrode layer containing the above binder, it canbe formed by adding an organic solvent dissolving the binder therein tothe electrode mixture material containing electrode active materialparticles, electrolyte particles and, if need, conducting particles suchas carbon particles to obtain an electrode paste, applying the electrodepaste onto a substrate, and then drying the same.

As another method, the solid electrolyte layer or the electrode layercan be formed by removing the organic solvent from the above electrolytepaste or the above electrode paste to obtain a solid matter, crushingthe obtained solid matter, and then press-molding the same into a mold.

In this case, since the organic polymer as the binder is dissolved inthe organic solvent, the organic polymer exists in the organic solventin a state that it electrically polarizes. As a result, a degree ofpolarization (adsorption potential) of the organic polymer affectspotentials of the solid electrolyte and the electrode active material.

Specifically, in the case where the solid electrolyte layer is formedusing a material containing the organic polymer in a polarized state asthe binder, the organic polymer affects ion conductivity of the solidelectrolyte, as a result of which the ion conductivity of the solidelectrolyte layer has often been reduced. From the same reason,electrical resistivity of the formed electrode layer becomes high.

This is because the organic polymer in a polarized state reacts with thesolid electrolyte or the electrode active material, and thereby a statethat gateways of ion-conducting channels (paths) thereof are sealed bythe organic polymer is generated in the paste.

Therefore, in the case where the solid electrolyte layer or theelectrode layer is formed by drying such a paste, the above state ismaintained in the formed layer. As a result, in the case of theelectrode layer, impedance thereof is increased, whereas in the case ofthe solid electrolyte layer, the ion conductivity thereof is decreased.

For these reasons, internal resistance of the all-solid secondarybattery having such electrode layer and solid electrolyte layer becomesextremely high, and an output current thereof becomes low. Therefore,such an all-solid secondary battery lacks in practicality.

In order to solve such a problem, it may be conceived that the solidelectrolyte layer or the electrode layer is formed using a mixturematerial containing dried organic polymer particles as the binder.

However, if the mixture material is prepared by mixing the organicpolymer particles with the electrolyte particles or the electrode activematerial particles when forming the solid electrolyte layer or theelectrode layer, the organic polymer particles are bonded together inthe mixture material, as a result of which the electrolyte particles orthe electrode active material particles cannot be mixed with the organicpolymer particles sufficiently.

Therefore, the formed solid electrolyte layer or the electrode layercannot have excellent strength and a stable electrochemical property.This produces a problem in that an all-solid secondary batterymanufactured using such a solid electrolyte layer and/or such anelectrode layer also cannot have excellent strength and a stablecharge-discharge property.

SUMMARY

Accordingly, it is an object of the present invention to provide anelectrochemical device manufactured using an electrode layer in whichsevere increase of electrode resistance is prevented and/or a solidelectrolyte layer in which severe decrease of ion conductivity of asolid electrolyte is prevented.

An aspect of the present invention is directed to an electrochemicaldevice. The electrochemical device comprises a pair of electrode layers,and a solid electrolyte layer provided between the pair of electrodelayers, wherein at least one layer of the electrode layers and the solidelectrolyte layer is composed of first particles each providing afunction of the at least one layer, second particles and a binder whichis composed of an organic polymer and binds the first and secondparticles, and wherein the at least one layer is formed from a mixturematerial containing the first particles and binder particles, each ofthe binder particles including the second particle and the bindercarried on at least a part of a surface thereof.

This makes it possible to provide an electrochemical device manufacturedusing an electrode layer in which severe increase of electroderesistance is prevented and/or a solid electrolyte layer in which severedecrease of ion conductivity of a solid electrolyte is prevented.

In the above electrochemical device, it is preferred that the at leastone layer is the electrode layer, the first particles include electrodeactive material particles each providing the function of the electrodelayer, and the second particles include at least one kind selected fromthe group comprising electrochemically inactive conducting particles,electrochemically inactive insulating particles and electrolyteparticles.

This makes it possible to improve binding strength between the first andsecond particles through the binder, while reducing inhibition of anelectrochemical reaction by the binder in the electrode layer.

In the above electrochemical device, it is preferred that the at leastone layer is the solid electrolyte layer, the first particles includeelectrolyte particles each providing the function of the solidelectrolyte layer, and the second particles include at least one kindselected from the group comprising electrochemically inactive insulatingparticles and electrolyte particles.

This makes it possible to improve binding strength between the first andsecond particles through the binder, while reducing inhibition of anelectrochemical reaction by the binder in the solid electrolyte layer.

In the above electrochemical device, it is preferred that the organicpolymer is at least one kind selected from the group comprisingstyrene-based thermoplastic elastomer, polyolefin, polyamide, polyimideand hot-melt resin as a major component thereof.

This makes it possible to improve binding strength between the first andsecond particles through the binder, while reducing inhibition of anelectrochemical reaction by the binder in the electrode layer and/or thesolid electrolyte layer.

In the above electrochemical device, it is preferred that an amount ofthe binder to an amount of the mixture material is in the range of 0.5to 20 wt %.

This makes it possible to improve binding strength between the first andsecond particles through the binder, while reducing inhibition of anelectrochemical reaction by the binder in the electrode layer and/or thesolid electrolyte layer.

In the above electrochemical device, it is preferred that theelectrolyte particles are composed of a lithium-ion-conducting solidelectrolyte or a silver-ion-conducting solid electrolyte.

This makes it possible to obtain an electrochemical device having anexcellent property. Therefore, the electrochemical device of the presentinvention may be used for constructing various kinds of all-solidsecondary batteries, but is preferably used for a lithium-ion-conductingall-solid secondary battery (an all-solid lithium secondary battery) ora silver-ion-conducting all-solid secondary battery (an all-solid silversecondary battery). These all-solid secondary batteries can exhibitexcellent charge-discharge properties.

In the above electrochemical device, it is preferred that theelectrolyte particles are composed of a lithium-ion-conducting solidelectrolyte or a silver-ion-conducting solid electrolyte.

This makes it possible to obtain an electrochemical device having anexcellent property. Therefore, the electrochemical device may be usedfor constructing various kinds of all-solid secondary batteries, but ispreferably used for a lithium-ion-conducting all-solid secondary battery(an all-solid lithium secondary battery) or a silver-ion-conductingall-solid secondary battery (an all-solid silver secondary battery). Inthis case, these all-solid secondary batteries can exhibit excellentcharge-discharge properties.

In the above electrochemical device, it is preferred that thelithium-ion-conducting solid electrolyte contains at least one kind of acrystalline sulfide-based lithium-ion-conducting solid electrolyte andan amorphous sulfide-based lithium-ion-conducting solid electrolyte.

This makes it possible to obtain an electrochemical device having anelectrode layer in which severe decrease of an electrochemical propertyis prevented. Therefore, a lithium-ion-conducting all-solid secondarybattery (an all-solid lithium secondary battery) in which theelectrochemical device is used can exhibit an excellent charge-dischargeproperty.

In the above electrochemical device, it is preferred that thelithium-ion-conducting solid electrolyte contains at least one kind of acrystalline sulfide-based lithium-ion-conducting solid electrolyte andan amorphous sulfide-based lithium-ion-conducting solid electrolyte.

This makes it possible to obtain an electrochemical device having asolid electrolyte layer in which severe decrease of an electrochemicalproperty is prevented. Therefore, a lithium-ion-conducting all-solidsecondary battery (an all-solid lithium secondary battery) in which theelectrochemical device is used can exhibit an excellent charge-dischargeproperty.

It is preferred that the above electrochemical device is adapted to beused for constructing an electrochemical sensor, an electrochemicaltimer or an all-solid secondary battery.

The electrochemical device of the present invention may be used forconstructing various kinds of apparatuses, but is preferably used for anelectrochemical sensor, an electrochemical timer or an all-solidsecondary battery. In this case, these apparatuses can exhibit excellentproperties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section view showing molds for forming a solidelectrolyte layer of a battery device in the left side thereof, and avertical section view showing structural examples of the solidelectrolyte layer in the right side thereof.

FIG. 2 is a schematic view showing an apparatus for forming a solidelectrolyte layer and an electrode layer each having a sheet shape.

FIG. 3 is a vertical section view showing structural examples of anelectrode layer of a battery device in the left side thereof, and avertical section view showing molds for forming the electrode layer inthe left side thereof.

FIG. 4 is a vertical section view showing an all-solid secondary batteryhaving a coin shape, in which the electrochemical device according tothe present invention is used.

FIG. 5 is a vertical section view showing an all-solid secondary batteryhaving a square shape, in which the electrochemical device according tothe present invention is used.

FIG. 6 is a flowchart illustrating a method of manufacturing the batterydevice of the all-solid secondary battery in the left side thereof, anda vertical section view showing molds for forming the solid electrolytelayer of the battery device in the right side thereof.

FIG. 7 is a vertical section view showing an ion conductivity measuringcell for measuring ion conductivity of the solid electrolyte layer.

FIG. 8 is a graph showing an effect of an amount of a binder onsilver-ion conductivity in a silver-ion-conducting solid electrolytelayer.

FIG. 9 is a flowchart illustrating a method of manufacturing theall-solid secondary battery.

FIG. 10 is a graph showing an initial charge-discharge property of asilver-ion-conducting all-solid secondary battery.

FIG. 11 is a graph showing a property of a discharge voltage against adischarge current density of a silver-ion-conducting all-solid secondarybattery.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the electrochemical device according to the presentinvention will be described in detail with reference to preferredembodiments shown in the accompanying drawings.

The electrochemical device of the present invention includes a pair ofelectrode layers, and a solid electrolyte layer provided between thepair of electrode layers, wherein at least one layer of the electrodelayers and the solid electrolyte layer is composed of first particleseach providing a function of the at least one layer, second particlesand a binder which is composed of an organic polymer and binds the firstand second particles, and wherein the at least one layer is formed froma mixture material containing the first particles and binder particles,each of the binder particles including the second particle and thebinder carried on at least a part of a surface thereof.

Hereinafter, description will be representatively offered regarding acase that the electrochemical device of the present invention (anall-solid electrochemical device) is used for constituting an all-solidsecondary battery 1.

First, methods of forming the electrode layers and the solid electrolytelayer, and a method of manufacturing the electrochemical device will bedescribed below. Specifically, as the method of forming the solidelectrolyte layer, each of methods of forming a silver-ion-conductingsolid electrolyte layer and a lithium-ion-conducting solid electrolytelayer will be described.

First Embodiment

<1> Formation of Solid Electrolyte Layer

<1-i> Preparation of Binder Solution

Here, description will be made on preparation of a binder solution (anorganic polymer solution) to be used for producing the binder particlesin a dried state, each of the binder particles including the secondparticle (particulate structure) and the binder carried on at least apart of a surface thereof.

The binder solution is used for producing the binder particles in adried state. Each of the binder particles includes the second particleand the binder carried on at least a part of a surface thereof. Thebinder solution is obtained by dissolving the binder composed of theorganic polymer in an organic solvent.

The organic polymer is not particularly limited to a specific type, butexamples of the organic polymer include styrene-based thermoplasticelastomer such as styrene-butadiene-styrene block copolymer,styrene-isoprene-styrene block copolymer orstyrene-ethylene-butylene-styrene block copolymer, polyolefin,polyamide, polyimide, hot-melt resin, and the like.

Among these materials, a material containing one or more of them as amajor component thereof is preferably used as the organic polymerconstituting the binder.

A desired amount of the binder is dissolved in the organic solvent toprepare the binder solution. The organic solvent is not particularlylimited to a specific type. Examples of the organic solvent include:ketone-based solvent such as methylethylketone (MEK) or acetone;alcohol-based solvent such as ethylene glycol or diethylene glycol(DEG); aliphatic hydrocarbon-based solvent such as heptane or pentane;aromatic hydrocarbon-based solvent such as methylbenzene or xylene;amide-based solvent such as N,N-dimethylacetamide (DMA); sulfurcompound-based solvent such as dimethyl sulfoxide (DMSO) or sulfolane;mixture solvent containing two or more of the above solvents; and thelike.

An amount of the binder to be dissolved in the organic solvent to anamount of the organic solvent is preferably in the range of several to50 wt %, and more preferably in the range of 5 to 30 wt %.

<1-ii> Production of Binder Particles for Solid Electrolyte Layer

Next, the binder solution prepared in the step <1-i> and the secondparticles to be carried the binder are mixed with each othersufficiently to obtain a mixture solution, the organic solvent isremoved from the mixture solution so that it is dried to obtain a solidmatter, and then the solid matter is crushed using a milling machine.

In this step, the second particles are crushed so as to have a desiredparticle shape and a desired particle size, to thereby obtain the binderparticles. At this time, the second particles are downsized, and each ofthe downsized second particles carries the binder on a part of thesurface thereof.

The crush can be performed using a milling machine such as a planet ballmilling machine, a vibration ball milling machine or a jet millingmachine.

In the case where the binder particles are produced, at least one kindselected from the group comprising electrochemically inactive insulatingparticles and electrolyte particles are used as the second particles onwhich the binder is to be carried.

As the electrochemically inactive insulating particles, particles madeof metal oxide such as alumina, silica or zirconia can be preferablyused. Further, as the electrolyte particles, electrolyte particles to beused for the solid electrolyte layer can be preferably used.

An amount of the binder carried on the second particles to an amount ofan electrolyte mixture material to be used for forming the solidelectrolyte layer is preferably in the range of 0.5 to 25 wt %, morepreferably in the range of 0.5 to 20 wt %, even more preferably in therange of 1 to 15 wt %, and still more preferably in the range of 1 to 10wt %. This makes it possible to prevent severe decrease of ionconductivity of the formed solid electrolyte layer (the obtainedelectrolyte molded body).

As described above, the method I (the immersion method) of immersing thesecond particles into the binder solution (that is, the method of mixingthe second particles with the binder solution) is used, as the method ofcarrying the binder contained in the binder solution on the secondparticles.

In this regard, examples of an alternative method of carrying the binderon the second particles include a method II (an application method) ofapplying the binder solution on the surface of each second particle, amethod III (a spray method) of spraying the binder solution on thesurface of each second particle, and the like.

Further, in the case where the electrolyte particles are used as thesecond particles, for example, electrolyte particles composed of alithium-ion-conducting solid electrolyte (a lithium-ion conductor) orelectrolyte particles composed of a silver-ion-conducting solidelectrolyte (a silver-ion conductor) can be preferably used.

Examples of the lithium-ion conducting solid electrolyte include asulfide-based lithium-ion-conducting solid electrolyte such as alithium-ion-conducting solid electrolyte glass (e.g., Li₂S—SiS₂,Li₂S—SiS₂—LiI, Li₂S—SiS₂—LiBr, Li₂S—SiS₂—LiCl, Li₂S—SiS₂—B₂S₃—LiI,Li₂S—SiS₂—P₂S₅—LiI, Li₂S—B₂S₃, Li₂S—B₂S₃—LiI, Li₂S—P₂S₅, Li₂S—P₂S₅—LiI,Li₂S—P₂S₅—Z_(m)S_(n) (Z═Ge, Zn, Ga), Li₂S—GeS₂, Li₂S—SiS₂—Li₃PO₄ orLi₂S—SiS₂—Li_(x)MO_(y) (M=P, Si, Ge, B, Al, Ga, In)), a crystallinelithium-ion-conducting solid electrolyte containing these components, amixture of them, and the like.

It is preferred that the sulfide-based lithium-ion-conducting solidelectrolyte contains at least one kind of a crystalline sulfide-basedlithium-ion-conducting solid electrolyte and an amorphous sulfide-basedlithium-ion-conducting solid electrolyte. The crystalline sulfide-basedlithium-ion-conducting solid electrolyte has most superior lithium-ionconductivity and exhibits good moldability. Therefore, in the case wherethe battery device 2 of the all-solid secondary battery 1 ismanufactured using the crystalline sulfide-based lithium-ion-conductingsolid electrolyte, there is an advantage that an output current densitythereof can become high.

On the other hand, since the amorphous sulfide-basedlithium-ion-conducting solid electrolyte does not have anisotropic inion conductivity, it can form a good ion-conducting path between theelectrode active material. In addition, since the amorphoussulfide-based lithium-ion-conducting solid electrolyte exhibits highheat stability, in the case where an all-solid secondary battery 1 ismanufactured using it, the all-solid secondary battery 1 can exhibitexcellent storage stability.

In this regard, it is to be noted that in the case where the crystallinesulfide-based lithium-ion-conducting solid electrolyte and the amorphoussulfide-based lithium-ion-conducting solid electrolyte are used incombination, it becomes possible to enjoy all the advantages offered bythem. However, when these sulfide-based lithium-ion-conducting solidelectrolytes are used, it is preferred that the handling of thesulfide-based lithium-ion-conducting solid electrolytes is performed ina glove box into which a dried inert gas (e.g., an argon gas, a nitrogengas or a green gas) is filled.

Examples of the silver-ion-conducting solid electrolyte includeAgI—Ag_(n)XO₄ or AgI—Ag_(n)X₂O₄ (where the X represents W, Cr, Mo, P, V,Te, Se or As), Ag₄RbI₅ and the like, one or more kind of which may beused independently or in combination. Among them, it is preferred thatiodinated silver tungstate (Ag₆I₄WO₄) exhibiting good thermal stabilityis used as the silver-ion-conducting solid electrolyte.

Use of this silver-ion-conducting solid electrolyte makes it possible toimprove performance of the solid electrolyte layer and, eventually, aproperty (a charge-discharge property) of the all-solid secondarybattery 1. Further, iodinated silver tungstate is stable in the air andeasy to handle.

In this regard, it is to be noted that the above second particles (e.g.,the above electrolyte particles) are further crushed and downsize so asto have an average particle size of several micrometers to several tensmicrometers, and then the crushed particles are preferably used as thesecond particles.

<1-iii> Preparation of Electrolyte Mixture Material

In this step, using the binder particles produced in the step <1-ii>, anelectrolyte mixture material for forming the solid electrolyte layer isprepared.

Specifically, first, a desired amount of the electrolyte particles (theion-conducting solid electrolyte), i.e., the first particles eachproviding the function of the solid electrolyte layer is measured. Next,a desired amount of the binder particles produced in the step <1-ii> isadded to the electrolyte particles, and then the electrolyte particlesand the binder particles are mixed with each other and crushed tothereby obtain the electrolyte mixture material.

In this step, the electrolyte particles and the binder particles aredownsized. An average particle size of the downsized electrolyte andbinder particles is preferably in the range of 5 to 30 micrometers. Thesolid electrolyte layer obtained by press-forming such an electrolytemixture material can have excellent mechanical strength, whilepreventing severe decrease of ion conductivity thereof.

For this reason, in the downsized electrolyte and binder particles, theaverage particle size of the above range is a preferable range forforming the solid electrolyte layer having an excellent property.

It is preferred that the amount of the binder to the amount of theelectrolyte mixture material (the material for forming the solidelectrolyte layer) is set to the range of 1 to 15 wt %. This makes itpossible to obtain a solid electrolyte layer which is suitable topractical use.

Thereafter, the thus obtained electrolyte mixture material is driedsufficiently, and then is used for forming the solid electrolyte layerand the battery device (the electrochemical device) 2 of the all-solidsecondary battery 1.

<1-iv> Formation of Solid Electrolyte Layer

Next, formation of the solid electrolyte layer using the electrolytemixture material prepared in the step <1-iii> will be described.Hereinafter, description will be representatively offered regardingcases that a solid electrolyte layer having a disk shape and a solidelectrolyte layer having a sheet shape are formed.

FIG. 1 is a vertical section view showing molds for forming a solidelectrolyte layer of a battery device in the left side thereof, and avertical section view showing structural examples of the solidelectrolyte layer in the right side thereof.

FIG. 2 is a schematic view showing an apparatus for forming a solidelectrolyte layer and an electrode layer each having a sheet shape.

First, the case that the solid electrolyte layer 5 having the disk shapeis formed will be described.

In this case, a female mold 300 having a cylindrical hole 500 isprepared as shown in FIG. 1. Subsequently, a desired amount of theelectrolyte mixture material 100 prepared in the step <1-iii> is filledin the cylindrical hole 500 of the female mold 300 in a state that alower male mold 200 is inserted into the cylindrical hole 500 and fittedto the female mold 300.

Then, after a top surface of a layer formed of the electrolyte mixturematerial 100 is leveled, the upper male mold 400 is inserted into thecylindrical hole 500, and then the lower male mold 200 and the uppermale mold 400 are pressed using a press machine so that the electrolytemixture material 100 is molded, to thereby obtain a solid electrolytelayer 5.

At this time, a molding pressure is preferably 3 ton/cm² or more, andmore preferably 5 ton/cm² or more. By setting the molding pressure tothe above range, the electrolyte mixture material 100 can beappropriately compressed. This makes it possible to maintain excellention conductivity of the obtained solid electrolyte layer.

In this regard, it is to be noted that if a female mold having a squarehole is used instead of the female mold 300 having the cylindrical hole500, it is possible to obtain a solid electrolyte layer having a squareshape.

Through the above steps <1-i> to <1-iv>, it is possible to obtain asolid electrolyte layer 101 having a structure [A], among solidelectrolyte layers 101 to 104 having structures [A] to [D] shown in theright side of FIG. 1.

Further, in order to improve mechanical strength of the solidelectrolyte layer when folding it, the solid electrolyte layer may beformed so as to have a structure [B] (that is, a solid electrolyte layer102). The solid electrolyte layer 102 may be formed as follows.

In this case, the top surface of the solid electrolyte mixture material100 filled into the cylindrical hole 500 is leveled, an insulating mesh120 cut so as to have a predetermined size is inserted into thecylindrical hole 500 and put on the top surface, the upper male mold 400is inserted into the cylindrical hole 500, and then the lower male mold200 and the upper male mold 400 are pressed using a press machine sothat the electrolyte mixture material 100 is molded so as to bury theinsulating mesh 120 therein, to thereby obtain a solid electrolyte layer102.

In this regard, it is to be noted that examples of the insulating mesh120 include a woven fabric and a nonwoven fabric each made ofpolyethylene, polypropylene, polycarbonate or polystyrene. In this way,it is possible to obtain a solid electrolyte layer 102 having the diskshape and a structure [B] in which the insulating mesh 120 is providedin the inside thereof.

Examples of a solid electrolyte layer having an alternative structure,which is used for constituting a secondary battery 2, include a solidelectrolyte layer 103 having a structure [C] in which a recess portionis provided on one surface thereof or a solid electrolyte layer 104having a structure [D] in which recess portions are provided on bothsurfaces thereof.

For example, the solid electrolyte layer 104 having the structure [D]can be formed by using two male molds 410 each having a protrusionportion 402, instead of the male molds 200 and 400 for the female mold300 shown in FIG. 1.

First, a desired amount of the electrolyte mixture material 100 preparedin the step <1-iii> is filled in the cylindrical hole 500 of the femalemold 300 in a state that one male mold 410 as a lower mold is insertedinto the cylindrical hole 500 and fitted to the female mold 300.

Then, after a top surface of a layer formed of the electrolyte mixturematerial 100 is leveled, the other male mold 410 as the upper mold isinserted into the cylindrical hole 500, and then the two male molds 410are pressed using a press machine so that the electrolyte mixturematerial 100 is molded, to thereby obtain the solid electrolyte layer104 having the structure [D].

On the one hand, the solid electrolyte layer 103 in which the recessportion is provided on the one surface thereof can be formed by usingthe male mold 410 as the upper mold and the male mold 200 as the lowermold.

When these solid electrolyte layers 103 and 104 are formed, a moldingpressure is preferably 3 ton/cm² or more, and more preferably 5 ton/cm²or more. By setting the molding pressure to the above range, theelectrolyte mixture material 100 can be appropriately compressed. Thismakes it possible to maintain excellent ion conductivity of each of theobtained solid electrolyte layers 103 and 104.

In the case where each of the solid electrolyte layers 103 and 104having such structures is provided between a pair of the electrodelayers, at least one of the electrode layers is inserted into the recessportion of the solid electrolyte layer 103 or 104 having electricalinsulation so as to cover a peripheral portion of the one electrodelayer.

As a result, it is possible to easily prevent occurrence of electricalshort-circuit between the electrode layers. Therefore, the solidelectrolyte layers 103 and 104 can be preferably used for manufacturingthe battery device 2 (or constituting the all-solid secondary battery1).

Next, the solid electrolyte layer having the sheet shape can be formedas follows. First, the electrolyte mixture material 100 prepared in thestep <1-iii> is applied onto a release paper 6000, and then it isuniformly leveled using a coater so as to become an average thickness ofabout 1 to 2 mm.

Thereafter, as shown in FIG. 2, the electrolyte mixture material 100applied on the release paper 6000 is passed between rollers 11 and 12whose distance is adjusted together with the release paper 6000, andthey are compressed. In this way, in is possible to form a solidelectrolyte layer having a sheet shape and a desired thickness.

Further, in order to improve mechanical strength of the solidelectrolyte layer having the sheet shape when folding it, the solidelectrolyte layer, in which the same insulating mesh (e.g., a wovenfabric and a nonwoven fabric each made of polyethylene, polypropylene,polycarbonate or polystyrene) as the insulating mesh 120 is providedtherein, is used.

Such a solid electrolyte layer having the sheet shape and the insulatingmesh can be formed as follows. Namely, before the electrolyte mixturematerial 100 is compressed, the insulating mesh has been, in advance,laminated thereto, and then they are passed between the rollers 11 and12 to obtain a solid electrolyte sheet.

Thereafter, the thus obtained solid electrolyte sheet is cut in apredetermined size, and then it is provided between the pair of theelectrodes, to thereby obtain a battery device (that is, theelectrochemical device of the present invention) 2 of an all-solidsecondary battery 1.

<2> Formation of Electrode Layers

<2-i> Preparation of Binder Solution

A binder solution to be used for producing binder particles in a driedstate is prepared in the same manner as in the above step <1-i>.Specifically, this binder solution is prepared using the same organicsolvent and binder as those used in the above step <1-i>. Further, acomposition of the binder solution to be prepared in the step <2-i>makes equal to that of the binder solution prepared in the above step<1-i>.

<2-ii> Production of Binder Particles for Electrode Layers

Next, the binder solution prepared in the step <2-i>, in which thebinder is dissolved in the organic solvent, and the second particles tobe carried the binder are mixed with each other sufficiently to obtain amixture solution, the organic solvent is removed from the mixturesolution so that it is dried to obtain a solid matter, and then thesolid matter is crushed using a milling machine.

In this step, the second particles are crushed so as to have a desiredparticle shape and a desired particle size, to thereby obtain the binderparticles. At this time, the second particles are downsized, and each ofthe downsized second particles carries the binder on a part of thesurface thereof.

As the second particles to be used for producing the binder particles,it is possible to use electrode active material particles orelectron-conducting particles, in addition to the electrochemicallyinactive insulating and electrolyte particles used for producing thebinder particles for the solid electrolyte layer in the step <1-ii>.

In the case where at least one of electrode layers of a battery device2, which is one example of electrochemical devices, is formed using theelectrode active material particles or the electron-conducting particlesas the second particles, it is possible to reduce a charge-dischargecapacity and internal resistance of the battery device 2. Therefore,these particles are especially preferably used as the second particles.

An amount of the binder carried on the second particles to an amount ofan electrode mixture material to be used for forming the electrode layeris preferably in the range of 0.5 to 25 wt %, more preferably in therange of 0.5 to 20 wt %, even more preferably in the range of 1 to 15 wt%, and still more preferably in the range of 1 to 10 wt %. This makes itpossible to prevent severe decrease of electric resistance of the formedelectrode layer (the obtained electrode molded body).

As described above, as the second particles on which the binder is to becarried, at least one kind selected from the group comprising theelectrode active material particles, the electrolyte particles, theelectron-conducting particles (the electrochemically inactive conductingparticles) and the insulating particles (the electrochemically inactiveinsulating particles) can be used. These particles are used inmanufacturing various kinds of the electrochemical devices.

In the case where a battery device of a silver-ion-conducting all-solidsecondary battery is constituted as the electrochemical device, examplesof an electrode active material to be used for forming the electrodelayers include δ-type silver vanadate (δ-Ag_(0.7)V₂O₅), metallic silver(Ag), silver chromate (Ag₂Cr₂O₄), and the like, one or more of which maybe used independently or in combination. Among them, it is desirable touse the δ-type silver vanadate (particularly, δ-Ag_(0.7)V₂O₅) as theelectrode active material.

Use of this compound makes it possible to improve s property of each ofthe electrode layers (the cathode and anode layers). As a result, it ispossible to enhance a property (a charge-discharge property) of thesilver-ion-conducting all-solid secondary battery. Moreover, the δ-typesilver vanadate is less environmentally detrimental, more stable in theair and easier to handle than the silver chromate.

In the case where a battery device of a lithium-ion-conducting all-solidsecondary battery is constituted as the electrochemical device, examplesof a cathode active material constituting the second particles to beused for forming the cathode layer include: transition metal oxidematerials such as lithium cobaltate (Li_(x)CoO₂), lithium nickelate(Li_(x)NiO₂), lithium nickel cobaltate (LiCo_(0.3)Ni_(0.7)O₂), lithiummanganate (LiMn₂O₄), lithium titanate (Li_(4/3)Ti_(5/3)O₄), lithiummanganate compound (LiM_(y)Mn_(2-y)O₄, where the M is Cr, Co or Ni),lithium iron phosphate and olivine compound, which is one kind oflithium iron phosphate compound (Li_(1-x)FePO₄ andLi_(1-x)Fe_(0.5)Mn_(0.5)PO₄); sulfide-based chalcogen compounds such asTiS₂, VS₂, FeS and M.MoS₈ (where the M is a transition metal such as Li,Ti, Cu, Sb, Sn, Pb or Ni); and lithium metal oxides containing metaloxides such as TiO₂, Cr₃O₈, V₂O₅, MnO₂ and CoO₂ as their skeleton; andthe like, one or more of which may be used independently or incombination.

On the other hand, examples of an anode active material constituting thesecond particles to be used for forming the anode layer include:metallic materials such as indium, tin, zinc, aluminum, silicon andgermanium, intermetallic alloys of these metallic materials, metallicoxides of these metallic materials, and the like, one or more of whichmay be used independently or in combination.

In the case where the electrolyte particles are used as the secondparticles on which the binder is to be carried, examples of a solidelectrolyte constituting them include: the silver-ion-conducting solidelectrolyte (the silver-ion conductor), described in the step <1-i>,such as the AgI—Ag_(n)XO₄ or AgI—Ag_(n)X₂O₄ (where the X represents W,Cr, Mo, P, V, Te, Se or As) or the Ag₄RbI₅; the lithium-ion-conductingsolid electrolyte (the lithium-ion conductor), described in the step<1-i>, such as the lithium-ion conducting solid electrolyte glass (e.g.,Li₂S—SiS₂, Li₂S—SiS₂—LiI, Li₂S—SiS₂—LiBr, Li₂S—SiS₂—LiCl,Li₂S—SiS₂—B₂S₃—LiI, Li₂S—SiS₂—P₂S₅—LiI, Li₂S—B₂S₃, Li₂S—B₂S₃—LiI,Li₂S—P₂S₅, Li₂S—P₂S₅LiI, Li₂S—P₂S₅—Z_(m)S_(n) (Z═Ge, Zn, Ga), Li₂S—GeS₂,Li₂S—SiS₂—Li₃PO₄ or Li₂S—SiS₂—Li_(x)MO_(y) (M=P, Si, Ge, B, Al, Ga,In)), the crystalline lithium-ion-conducting solid electrolytecontaining these components or the mixture of them; and the like.

Further, in the case where the electron-conducting particles are used asthe second particles on which the binder is to be carried, examples of aconducting material constituting them include titanium, vanadium, iron,manganese, nickel, copper, aluminum, silicon, zinc, gallium, germanium,silver, indium, tin, antimony, and the like. These conducting materialscan be appropriately selected in view of an electrochemical reaction inthe all-solid secondary battery to be manufactured.

Furthermore, in the case where the insulating particles are used as thesecond particles on which the binder is to be carried, examples of aninsulating material constituting them include an insulating metallicoxide such as alumina, silica or zirconia, and the like.

<2-iii> Preparation of Electrode Mixture Material

In general, an electrode layer of an all-solid secondary battery may beformed by an electrode mixture material containing electrolyte particles(ion-conducting electrolyte particles), electrode active materialparticles and, if need, electron-conducting particles such as carbonparticles.

Further, the electrode layer may be formed by preparing a slurry inwhich the electrode mixture material is mixed with a binder solution (anorganic polymer solution) containing a binder, applying and drying theslurry to obtain a solid matter, compressing and rolling the solidmatter, if need, to obtain an electrode sheet, and then cutting theelectrode sheet to a required shape and a required size.

However, in the present invention, the electrode layer is formed usingan electrode mixture material containing the binder particles producedin the step <2-ii> and electrode active material particles, i.e., thefirst particles providing the function of the electrode layer.

Specifically, first, desired amounts of the electrolyte particles (theion-conducting electrolyte particles) and electrode active materialparticles are measured. Next, a desired amount of the binder particlesproduced in the step <2-ii> is added to the same, and then theelectrolyte particles, the electrode active material particles and thebinder particles are mixed with each other and crushed to thereby obtainthe electrode mixture material. In this step, the electrolyte particles,the electrode active material particles and the binder particles aredownsized.

In this case, a mixing ratio (a mole ratio) of an amount of theelectrolyte particles to an amount of the electrode active materialparticles is preferably in the range of 1:9 to 4:6. By setting themixing ratio to the above range, it is possible to enhance a batterycapacity of an all-solid secondary battery 1 to be manufactured.

Further, the mixing ratio of the amount of the electrolyte particles tothe amount of the electrode active material particles is more preferablyin the range of 1:9 to 5:5. This makes it possible to obtain anall-solid secondary battery 1 having practical capacity.

Furthermore, the amount of the binder (the organic polymer) to theamount of the electrode mixture material (the material for forming theelectrode layer) is particularly preferably in the range of 1 to 25 wt%. This makes it possible to obtain an electrode layer having apractical property in electrical conductivity.

An average particle size of the downsized electrolyte, electrode activematerial and binder particles is preferably in the range of 5 to 30micrometers. The electrode layer obtained by press-forming such anelectrode mixture material can have excellent mechanical strength, whilepreventing severe increase of electrical resistance thereof.

For this reason, in the downsized electrolyte, electrode active materialand binder particles, the average particle size of the above range is apreferable range for forming the electrode layer having an excellentproperty.

Thereafter, the thus obtained electrode mixture material is driedsufficiently, and then used for forming the electrode layer.

In the case where the above electrode layer is used as a cathode layeror an anode layer, a combination of a cathode active material (that is,the electrode active material to be used for forming the cathode layer)and an anode active material (that is, the electrode active material tobe used for forming the anode layer) is not particularly limited to aspecific combination.

Among materials having different electrochemical reaction potentials, amaterial having electropositive potential is selected as the cathodeactive material, whereas a material having electronegative potential isselected as the anode active material, and these materials are used incombination. This makes it possible to obtain an all-solid secondarybattery 1 having an arbitrary discharge voltage.

In the case where a battery device of a lithium-ion-conducting all-solidsecondary battery is constituted as the electrochemical device, examplesof the cathode active material constituting the first particles to beused for forming the cathode layer include: transition metal oxidematerials such as lithium cobaltate (Li_(x)CoO₂), lithium nickelate(Li_(x)NiO₂), lithium nickel cobaltate (LiCo_(0.3)Ni_(0.7)O₂), lithiummanganate (LiMn₂O₄), lithium titanate (Li_(4/3)Ti_(5/3)O₄), lithiummanganate compound (LiM_(y)Mn_(2-y)O₄, where the M is Cr, Co or Ni),lithium iron phosphate and olivine compound, which is one kind oflithium iron phosphate compound (Li_(1-x)FePO₄ andLi_(1-x)Fe_(0.5)Mn_(0.5)PO₄); sulfide-based chalcogen compound such asTiS₂, VS₂, FeS and M.MoS₈ (where the M is a transition metal such as Li,Ti, Cu, Sb, Sn, Pb or Ni); and lithium metal oxides containing metaloxides such as TiO₂, Cr₃O₈, V₂O₅, MnO₂ and CoO₂ as their skeleton; andthe like, one or more of which may be used independently or incombination.

On the other hand, examples of the anode active material constitutingthe first particles to be used for forming the anode layer include:metallic materials such as indium, tin, zinc, aluminum, silicon andgermanium, intermetallic alloys of these metallic materials, andmetallic oxides of these metallic materials, and the like, one or moreof which may be used independently or in combination.

Further, in the case where a battery device of a silver-ion-conductingall-solid secondary battery is constituted as the electrochemicaldevice, examples of the electrode active material constituting the firstparticles to be used for forming the electrode layers (the cathode andanode layers) include δ-type silver vanadate (δ-Ag_(0.7)V₂O₅), metallicsilver (Ag), silver chromate (Ag₂Cr₂O₄), and the like, one or more ofwhich may be used independently or in combination. Among them, it isdesirable to use the δ-type silver vanadate (particularly,δ-Ag_(0.7)V₂O₅) as the electrode active material.

Use of this compound makes it possible to improve a property of each ofthe electrode layers (the cathode and anode layers). As a result, it ispossible to enhance a property (a charge-discharge property) of thesilver-ion-conducting all-solid secondary battery. Moreover, the δ-typesilver vanadate is less environmentally detrimental, more stable in theair and easier to handle than silver chromate.

Examples of the solid electrolyte constituting the electrolyte particlescontained in the electrode layers (the cathode and anode layers)include: the silver-ion-conducting solid electrolyte, described above,such as the AgI—Ag_(n)XO₄ or the AgI—Ag_(n)X₂O₄ (where the X representsW, Cr, Mo, P, V, Te, Se or As) or the Ag₄RbI₅; thelithium-ion-conducting solid electrolyte such as the lithium-ionconducting solid electrolyte glass (e.g., Li₂S—SiS₂, Li₂S—SiS₂—LiI,Li₂S—SiS₂—LiBr, Li₂S—SiS₂—LiCl, Li₂S—SiS₂—B₂S₃—LiI, Li₂S—SiS₂—P₂S₅—LiI,Li₂S—B₂S₃, Li₂S—B₂S₃—LiI, Li₂S—P₂S₅, Li₂S—P₂S₅—LiI, Li₂S—P₂S₅—Z_(m)S_(n)(Z═Ge, Zn, Ga), Li₂S—GeS₂, Li₂S—SiS₂—Li₃PO₄, and Li₂S—SiS₂—Li_(x)MO_(y)(M=P, Si, Ge, B, Al, Ga, In)), the crystalline lithium-ion-conductingsolid electrolyte containing these components or the mixture of them;and the like.

<2-iv> Formation of Electrode Layer

Next, formation of the electrode layer using the electrode mixturematerial prepared in the step <2-iii> will be described. Hereinafter,description will be representatively offered regarding cases that anelectrode layer having a disk shape and an electrode layer having asheet shape are formed.

Molds shown in the right side of FIG. 3 can be used for forming theseelectrode layers, these molds have the same structures as those of themolds used for forming the solid electrolyte layer shown in FIG. 1.

In this regard, it is preferred that the female mold having acylindrical hole with an inside diameter smaller than that of thecylindrical hole 500 of the female mold 300 shown in FIG. 1 is used, ifneed. In an all-solid secondary battery having a cathode layer and ananode layer each formed using such molds, it is possible to reliablyprevent occurrence of short-circuit between the cathode layer and theanode layer.

In this case, a female mold 301 having a cylindrical hole 501 isprepared as shown in FIG. 3. Subsequently, a desired amount of theelectrode mixture material 600 prepared in the step <2-iii> is filled inthe cylindrical hole 501 of the female mold 301 in a state that a lowermale mold 201 is inserted into the cylindrical hole 501 and fitted tothe female mold 301.

Then, after a top surface of a layer formed of the electrode mixturematerial 600 is leveled, the upper male mold 401 is inserted into thecylindrical hole 501, and then the lower male mold 201 and the uppermale mold 401 are pressed using a press machine so that the electrodemixture material 600 is molded, to thereby obtain an electrode layer.

Through the above steps <2-i> to <2-iv>, it is possible to obtain anelectrode layer 601 having a disk shape and a structure [E] shown in theleft side of FIG. 3.

Further, in order to reduce electrical resistance of the electrode layeror improve mechanical strength thereof when folding it, the electrodelayer may be formed so as to have a structure [F] (that is, an electrodelayer 602). The electrode layer 602 may be formed as follows.

In this case, the top surface of the layer formed of the electrodemixture material 600 filled into the cylindrical hole 501 is leveled, acollector formed from a conducting mesh member 6341 cut so as to have apredetermined size is inserted into the cylindrical hole 501 and put onthe top surface, and then the lower male mold 201 and the upper malemold 401 are pressed using a press machine so that the electrode mixturematerial 600 is molded so as to bury the conducting mesh member 6341therein, to thereby obtain the electrode layer 602.

At this time, a molding pressure is preferably 3 ton/cm² or more, andmore preferably 5 ton/cm² or more. By setting the molding pressure tothe above range, the electrode mixture material 600 can be appropriatelycompressed, and also be reliably filled into through-holes of thecollector formed from the conducting mesh member 6341 if it is used.

Further, as shown in the left side of FIG. 3, electrode layers 603 to606 having structures [G] to [J] can be formed. For example, theelectrode layer 603 having the structure [G] can be formed in the samemanner as in the electrode layer 602 having the structures [F], exceptthat a collector, in which an electrode lead board 6342 formed from aconducting thin film is joined (united) to the conducting mesh member6341 used in the structure [F] using a spot welding, is used.

Furthermore, each of the electrode layers 604 to 606 having thestructures [H] to [J] is an electrode layer including each of thestructures [E] to [G], and a flame member (an electrode flame) 6348provided along a periphery portion thereof.

This flame member serves as a restrictor that restricts a volume changeof the electrode layer which would be generated due to a change incrystal structures of the electrode active material when anelectrochemical reaction occur in the electrode layer. Therefore, byproviding the flame member 6348 in the electrode layer, it is possibleto improve mechanical strength thereof.

As the conducting mesh member 6341, a woven mesh made of anelectron-conducting metallic material such as Cu, Ni, Ti or SUS or anexpanded mesh utilizing a conducting thin film can be used. Further, thecollector can be formed from a conducting thin film having a pluralityof recess portions, into which the electrode mixture material is filled,provided on a surface thereof, instead of the conducting mesh member6341.

In this regard, the conducting mesh member 6341 can be formed by weavinga plurality of thin lines made of the electron-conducting metallicmaterial. Further, the recess portions provided on the surface of theconducting thin film can be formed by compressing it using a pressmachine.

Further, as long as such a collector has conductivity at least on asurface thereof, it may be a member made of a conducting material in itsentirety, or a member including a core whose surface is coated with aconducting layer.

Examples of the core include: a woven fabric and a nonwoven fabric eachmade of a hard resin material such as polyethylene, polypropylene,polycarbonate or polystyrene; a insulating thin film made of a ceramicsuch as alumina or glass and having the recess portions on the surfacethereof.

An occupation percentage of the through-holes or the recess portions ofthe collector in a plan view is preferably in the range of about 25 to90%, and more preferably in the range of about 50 to 85%, although itmay slightly vary depending on the constituent material and intended useof the collector.

Further, an average thickness of the collector is preferably in therange of about 50 to 400 μm, and more preferably in the range of about100 to 200 μm, although it may be slightly changed depending on theconstituent material and intended use of the collector.

Next, the electrode layer having the sheet shape can be formed using theapparatus shown in FIG. 2, that is, the same apparatus as one used forforming the solid electrolyte layer having the sheet shape.

First, the electrode mixture material 600 produced in the step <2-iii>is applied onto a release paper 6000, and then it is uniformly leveledusing a coater so as to become an average thickness of about 1 to 2 mm.

Thereafter, the electrode mixture material 600 provided on the releasepaper 6000 is passed between rollers 11 and 12 whose distance isadjusted together with the release paper 6000, and they are compressed.In this way, it is possible to form an electrode layer having a sheetshape and a desired thickness.

Further, in order to improve mechanical strength of the electrode layerhaving the sheet shape when folding it and to reduce electricalresistance thereof, the electrode layer, in which a conducting meshmember such as a metallic mesh or a metallic expanded mesh is provided,is used.

Such an electrode layer having the sheet shape can be formed as follows.Namely, before the electrode mixture material 600 is compressed, theconducting mesh member (the collector) has been, in advance, laminatedthereto, and then they are passed between the rollers 11 and 12 toobtain a electrode sheet. Thereafter, the thus obtained electrode sheetis cut in a predetermined size, to thereby obtain an electrode layer.

<3> Manufacture of Battery Device

The battery device 2 of the all-solid secondary battery 1 has a basicstructure including a pair of a cathode layer and an anode layer, and asolid electrolyte layer provided between the cathode layer and the anodelayer.

The battery device 2 is manufactured by forming the solid electrolytelayer through the above steps <1-i> to <1-iv> and the cathode and anodelayers through the above steps <2-i> to <2-iv>, respectively, and thenpressing the cathode and anode layers and the solid electrolyte layerprovided (interposed) therebetween to thereby join them together.

At this time, although all of the solid electrolyte layers 101 to 104having the structures [A] to [D] shown in FIG. 1 can be used as thesolid electrolyte layer, it is preferred that the solid electrolytelayers 103 and 104 having the structures [C] and [D] are used.

This makes it possible to prevent occurrence of short-circuit whichwould be easily generated between the cathode layer and the anode layerwhen the battery device 2 of the all-solid secondary battery 1 is inuse.

On the other hand, although all of the electrode layers 601 to 606having the structures [E] to [J] shown in FIG. 3 can be used as each ofthe cathode layer and the anode layer, it is preferred that theelectrode layers 603 and 604 having the structures [G] and [H] are used.

This makes it possible to improve mechanical strength of each of thecathode layer and the anode layer against expansion and contraction ofthe electrode active material when the battery device 2 of the all-solidsecondary battery 1 is in use (charge-discharge operation). As a result,it is possible to extend life in charge-discharge cycles of the batterydevice 2 (the all-solid secondary battery 1).

FIGS. 4 and 5 are, respectively, a vertical section view showing anall-solid secondary battery having a coin shape and a vertical sectionview showing an all-solid secondary battery having a square shape.

Hereinafter, description will be made on structures and methods ofmanufacturing these all-solid secondary batteries 1. The all-solidsecondary battery 1 shown in FIG. 4 has a coin-shaped structure, and theall-solid secondary battery 1 shown in FIG. 5 has a square-shapedstructure.

In FIG. 4, numeral references 3 and 4, respectively, show the cathodelayer and the anode layer, and a numeral reference 5 shows the solidelectrolyte layer.

Numeral references 6031, 6032, 6033 and 6034, respectively, show aconducting expanded mesh used as a cathode collector, a cathode leadboard, a cathode mixture material and a cathode extraction lead.

Further, numeral references 6041, 6042, 6043 and 6044, respectively,show a conducting expanded mesh used as an anode collector, an anodelead board, an anode mixture material and an anode extraction lead.

Numerals 6080 and 6090, respectively, show a restrictor and a fixedportion. Numerals 90 and 91, respectively, show a container body of acoin type battery container which also serves as an anode terminal and alid (a sealing plate) which also serves as a cathode terminal. A numeralreference 17 shows an insulating packing.

Further, the all-solid secondary battery having the square shape shownin FIG. 5 includes a cathode layer 3 having a square shape, an anodelayer 4 having a square shape, and a solid electrolyte layer 5 having asquare shape and provided therebetween. Numerals 3E and 4E,respectively, show a cathode terminal and an anode terminal.

These terminals 3E and 4E are secured to the lid 91 for the containerbody 90 through insulating tubes 93 in a liquid-tight state. Further,the lid 91 is fixed to the container body 90 through an adhesive agent,a packing agent or a weld metal.

FIG. 6 is a flowchart illustrating a method of manufacturing the batterydevice of the all-solid secondary battery in the left side thereof, anda vertical section view showing molds for forming the solid electrolytelayer of the battery device in the right side thereof. FIG. 9 is aflowchart illustrating a method of manufacturing the all-solid secondarybattery.

The method of manufacturing the all-solid secondary battery shown inFIG. 9 includes: <a> an anode layer forming step 10 for forming theanode layer; <b> a cathode layer forming step 20 for forming the cathodelayer; <c> a battery device manufacturing step 30 for manufacturing thebattery device (the all-solid battery device) by forming the solidelectrolyte layer and then joining the solid electrolyte layer and thethus formed anode and cathode layers together; <d> a restrictor formingstep 40 for forming the restrictor so as to cover almost all of thebattery device; <e> a battery device receiving step 50 for receiving thebattery device with the restrictor into the container body; <f> abattery container sealing step 60 for sealing the battery containerwhile extracting the anode and cathode layers of the battery deviceexteriorly.

Hereinafter, the respective steps will be described one by one.

<a> Anode Layer Forming Step 10

<a1> Before the anode layer is formed, first, an anode mixture materialand a member which are necessary for forming the anode layer areprepared, respectively.

The anode mixture material is prepared by producing binder particles tobe used for forming the anode layer according to the step <2-ii> using abinder solution prepared in the step <2-i>, and then mixing anode activematerial particles and electrolyte particles each prepared independentlywith the binder particles according to the step <2-iii>.

Namely, the anode mixture material contains the anode active materialparticles, the electrolyte particles and the binder particles to be usedfor forming the anode layer.

Specifically, the anode mixture material can be prepared by measuringrequired amounts of the anode active material particles, the electrolyteparticles and the binder particles, and then mixing them with each otherusing a milling machine (a mixing machine) such as a planet ball millingmachine.

A mixing ratio of an amount of the electrolyte particles to an amount ofthe anode active material particles is preferably in the range of 1:9 to5:5. Further, an amount of the binder to an amount of the anode mixturematerial is preferably in the range of 0.5 to 25 wt %, and morepreferably in the range of 1 to 10 wt %.

This makes it possible to maintain an ion-conducting path existing inthe anode mixture material in a good state, while reducing internalresistance in the formed anode layer.

In the anode mixture material prepared in this way, it is possible toprevent contact of the anode active material particles with the bindersolvated by the organic solvent. This makes it possible to reliablyprevent sealing of gateways of ion-conducting channels (paths) of theanode active material particles by the binder in a polarized state.

<a2> Next, an anode collector to be used for burying in the anode layeris prepared.

A metallic expanded mesh having an occupation percentage of thethrough-holes of 75% has been, in advance, prepared by processing andcutting a copper foil having a thickness of 70 micrometers. Further, acopper foil having the same size as that of the metallic expanded meshand a thickness of 50 micrometers is prepared as an anode lead board.

Next, the metallic expanded mesh and the anode lead board are bondedtogether at a plurality of points by a spot welding to thereby obtainthe anode collector.

By forming an anode layer using such anode collector and anode mixturematerial, it is possible to preferably prevent enhancement of impedancein the formed anode layer. This makes it possible to prevent enhancementof internal resistance in a battery device with such an anode layer. Asa result, a battery device having an excellent property can be obtained.

<a3> Next, molds to be used for forming the anode layer are prepared asshown in the right side of FIG. 3. Subsequently, the anode mixturematerial (the electrode mixture material 600) is filled in a cylindricalhole 501 of a female mold 301 in a state that a lower male mold 201 isinserted into the cylindrical hole 501.

Then, after a top surface of a layer formed of the anode mixturematerial is leveled, the anode collector is inserted into thecylindrical hole 501 so that the metallic expanded mesh is positioned onthe side of the anode mixture material.

Thereafter, the upper male mold 401 is inserted into the cylindricalhole 501, and then the lower male mold 201 and the upper male mold 401are pressed using a press machine so that the anode mixture material ismolded.

In this way, it is possible to obtain a anode layer having a disk shapeand a structure [E] (that is, an electrode layer 603 having the diskshape) in which the anode mixture material is filled into thethrough-holes of the metallic expanded mesh of the anode collector bycompression.

At this time, a molding pressure is preferably 3 ton/cm² or more, andmore preferably 5 ton/cm² or more. By setting the molding pressure tothe above range, the anode mixture material can be appropriatelycompressed, and also be filled into the through-holes of the metallicexpanded mesh of the anode collector reliably.

In this regard, it is to be noted that a constituent material of each ofthe molds used for forming the anode layer is not limited to a metallicmaterial, and may be a resin material or a ceramic material.

The thus obtained anode layer is removed from the cylindrical hole 501of the female mold 301, and is used for manufacturing the battery deviceof the all-solid secondary battery.

<b> Cathode Layer Forming Step 20

In this step, the cathode layer is formed in the same manner as in theabove step <a>, that is, the anode layer forming step 10, except that acathode active material particles are used instead of the anode activematerial particles as the electrode active material particles.

Namely, the cathode active material particles are prepared instead ofthe anode active material particles, and the cathode layer is formed inthe same manner as the above anode layer using a cathode mixturematerial containing the cathode active material particles.

<c> Battery Device Manufacturing Step 30

<c1> First, according to the step <2-iii>, an electrolyte mixturematerial is prepared by mixing electrolyte particles with the binderparticles to be used for forming the solid electrolyte layer, which thebinder particles are prepared in the step <1-ii>.

<c2> Next, as molds to be used for manufacturing the battery device,molds shown in the left side of FIG. 6 are prepared. In this embodiment,in order to form a solid electrolyte layer having two recess portions,into each of which the cathode layer or the anode layer is inserted, onboth of surfaces thereof, two male molds 4006 each having a protrusionportion 4007 are used as lower and upper male molds.

In this regard, it is to be noted that the male molds 4006 each havingthe protrusion portion 4007 with an exterior shape equal to or slightlylarger than that of the cathode and anode layers are used.

<c3> Next, the electrolyte mixture material 1000 is filled in acylindrical hole 1005 of a female mold 1003 in a state that one of thetwo male molds 4006 is inserted into the cylindrical hole 1005.

Then, after a top surface of a layer formed of the electrolyte mixturematerial 1000 is leveled, the other male mold 4006 is inserted into thecylindrical hole 1005 and the two male molds 4006 are lightly pressed sothat the electrolyte mixture material 1000 is molded, to thereby obtaina solid electrolyte layer having a structure [D] shown in FIG. 1.

Thereafter, the other male mold 4006 is removed from the cylindricalhole 1005, and the cathode layer formed in the step <b>, in which thecathode collector obtained by joining the cathode lead board and themetallic expanded mesh together is buried, is inserted into one of therecess portions formed on one of the surfaces of the solid electrolytelayer.

Next, a male mold 1004 having no protrusion portion is inserted into thecylindrical hole 1005 and this male mold 1004 and the one male mold 4006are lightly pressed to thereby obtain a solid electrolyte layer having astructure [IV] shown in FIG. 6.

At this time, a molding pressure is preferably set to 3 ton/cm² or less.By setting the molding pressure to the above range, it is possible tofirmly join (unite) the anode layer and the solid electrolyte layertogether in the subsequent step.

Subsequently, the female mold 1003 is turned over so that the otherrecess portion formed on the other surface of the solid electrolytelayer, into which any member is not inserted, is positioned at an upperside. Then, the one male mold 4006 is removed from the cylindrical hole1005, and the anode layer formed in the step <a> is inserted into theother recess portion.

Next, a male mold 1004 having no protrusion portion is inserted into thecylindrical hole 1005 and the two male molds 1004 are pressed. In thisway, a battery device having a structure [V] shown in FIG. 6, in whichthe solid electrolyte layer interposed between the cathode layer and theanode layer, is manufactured.

<d> Restrictor Forming Step 40

<d1> This step is performed after the thus manufactured battery deviceis released from a compression state in the above battery devicemanufacturing step <c>.

As shown in FIGS. 4 and 5, first, a cathode extraction lead 6034,through which the cathode layer 3 and the cathode terminal 91 or 3E areto be electrically connected together, and an anode extraction lead6044, through which the anode layer 4 and the anode terminal 90 or 4Eare to be electrically connected together, are provided (attached) tothe battery device.

Next, a restrictor 6080 is formed so as to cover almost all of thebattery device other than the cathode extraction lead 6034 and the anodeextraction lead 6044.

In the case where the restrictor 6080 is made of, e.g., a hot-melt resin(a hot-melt adhesive agent) or a low-melting-point glass, it is possibleto form the restrictor 6080 by melting or softening the above material,supplying the same on an outer circumferential surface of the batterydevice and allowing the same to be cooled down and solidified.

According to this method, it is possible to reliably form the restrictor6080 so as to cover almost all of the battery device, as shown in FIGS.4 and 5.

Various kinds of methods can be used in order to supply the hot-meltresin or the low-melting-point glass in a melt or softened state (aliquid state) to the outer circumferential surface of the batterydevice.

Examples of these methods include: a method I of dipping the batterydevice into the hot-melt resin or the low-melting-point glass in aliquid state (that is, a dipping method); and a method II of coating thehot-melt resin or the low-melting-point glass in a liquid state on theouter circumferential surface of the battery device (that is, a coatingmethod).

Further, in the case where the restrictor 6080 is made of, e.g., athermosetting resin or a photocurable resin, it is possible to form therestrictor 6080 by supplying an uncured resin material in a liquid stateto the outer circumferential surface of the battery device and curingthe same through heating or light irradiation.

Use of this method also makes it possible to reliably form therestrictor 6080 so that it can cover almost all of the battery device.

Furthermore, by forming the restrictor 6080 by means of a vacuumencapsulation method, it is possible to prevent or suppress an airbubble (a space) from generating within the restrictor 6080. This makesit possible to improve mechanical strength of the restrictor 6080.

As a result, it is possible to restrict expansion of each of the solidelectrolyte layer 5, the cathode layer 3 and the anode layer 4 in theplane direction thereof reliably. Therefore, it is possible to provide abattery device which can prevent reduction of a battery capacity overthe lapse of charge-discharge cycles reliably.

The above-noted methods for supplying the hot-melt resin or thelow-melting-point glass in a liquid state can be equally used insupplying the uncured resin material to the outer circumferentialsurface of the battery device.

<e> Battery Device Receiving Step 50

Next, as shown in FIGS. 4 and 5, the battery device with the restrictor6080 is received into the container body 90 of the battery container 9.

<e1> First, the battery container 9 including the container body 90having a bottom-closed hollow cylindrical shape and a lid 91 for closinga top opening of the container body 90 is prepare.

<e2> Next, an uncured material of a resin material such as athermosetting resin or a photocurable resin is filled into the containerbody 90, and in this state, the battery device with the restrictor 6080formed in the step <d> is received into the container body 90.

<e3> Thereafter, the uncured material filled into the container body 90is cured so that the battery device with the restrictor 6080 is fixed tothe container body 90 through the fixed portion 6090.

<e4> Next, the lid 91 is placed on the container body 90. At this time,in the case of FIG. 5, the cathode extraction lead 6034 and the anodeextraction lead 6044 are, respectively, inserted into the insulatingtubes 93 and electrically connected to the cathode terminals 3E and theanode terminal 4E each secured to the lid 91 through insulating tubes93.

Further, in the case of FIG. 4, that is, the coin type battery container9, after the battery device with the restrictor 6080 is received intothe container body 90 of the battery container 9, particles made of thethermosetting resin may be filled into a space between the batterydevice with the restrictor 6080 and the container body 90.

<f> Battery Container Sealing Step 60

After the step <e> is preformed, the lid 91 and the container body 90 isbonded together using a adhesive agent or a packing agent whilecompressing them, to thereby seal the battery container 90.

Further, in the case where the particles made of the thermosetting resinare filled into the coin type battery container 9, after the batterycontainer 9 is sealed, the particles filled thereinto may be heatedtogether with the battery container 9 and the battery device, as aresult of which these particles are cured to form the fixed portion6090.

Furthermore, as alternative method, the all-solid secondary batteryshown in FIG. 5 can be completed as follows. Namely, first, the lid 91having a resin injection port is fixed to the container body 90 intowhich the battery device with the restrictor 6080 is received, so thatthe cathode extraction lead 6034 and the anode extraction lead 6044 are,respectively, electrically connected to the cathode terminal 3E and theanode terminal 4E each secured to the lid 91 through insulating tubes93. Next, a liquid resin is injected into the battery container 9 by avacuum encapsulation method (a degassing method) through the resininjection port, and then is cured. Thereafter, the resin injection portis sealed.

Through the above mentioned steps <a> to <f>, it is possible to obtainall-solid secondary batteries as shown in FIGS. 4 and 5.

Hereinbefore, although description has been made on a case that theelectrochemical device of the present invention is used in the all-solidsecondary battery, the present invention is not limited thereto.

The electrochemical device having the above solid electrolyte layer andthe above electrode layers as a basic structure thereof can bepreferably used in an electrical charge memory device, anelectrochemical sensor, an electrochemical timer, an electrochemicalactuator or an electrochemical display device in addition to theall-solid secondary battery.

Typical Experimental Procedures

Now, description will be made on concrete typical experimentalprocedures of the present invention in detail.

Experimental Procedure 1

In this Experimental procedure 1, a solid electrolyte layer usingelectrolyte particles (first particles) made of a silver-ion-conductingsolid electrolyte (a silver-ion conductor) will be described.

The silver-ion-conducting solid electrolyte such as iodinated silvertungstate (Ag₆I₄WO₄) is used. The silver-ion-conducting solidelectrolyte is received into an alumina pot and crushed using a planetball milling machine with alumina balls to obtain a crushed matter.

This crushed matter is screened to obtain particles. Particles having aparticle size of about 15 micrometers or less are utilized as theelectrolyte particles (the first particles) to be used for forming thesolid electrolyte layer.

On the other hand, particles having a particles size of about 15micrometers or more are utilized as second particles to be used forcarrying a binder composed of an organic polymer (that is, secondparticles to be used for producing binder particles).

Prior to producing the binder particles, first, block copolymer such asstyrene-butadiene-styrene block copolymer (SBR) is prepared as theorganic polymer consisting the binder, an organic solvent such astoluene is prepared for dissolving the binder, and then they are mixedwith each other to thereby obtain a solution containing the blockcopolymer.

Next, this solution (binder solution or polymer solution) and theelectrolyte particles (the second particles) to be used for carrying thebinder are sufficiently mixed with each other to obtain a mixturesolution, the organic solvent is evaporated and removed from the mixturesolution to obtain a solid matter, and then the solid matter is crushedusing a freeze crusher in the size of about 20 micrometers or less. Inthis way, the binder particles to be used for forming the electrolytelayer are obtained.

Subsequently, the electrolyte particles and the binder particles aremixed with each other in various ratios to prepare electrolyte mixturematerials. Each of the electrolyte mixture materials is formed in theform of a disk having a diameter of about 10 mm according to the methodof forming the solid electrolyte layer described in the aboveembodiment, to thereby obtain various solid electrolyte layers eachhaving a structure [A] shown in FIG. 1 and a different amount of thebinder.

Ion conductivity is measured for each of the thus obtained solidelectrolyte layers using an ion conductivity measuring cell shown inFIG. 7.

As shown in FIG. 7, the ion conductivity measuring cell includes acircular cylinder 3001 made of PET with an external diameter of 35 mmand having a cylindrical hole with an internal diameter of 10 mm, probes3002 and 3003 each made of SUS and being to be inserted into an one endof the cylindrical hole as an electrochemically inactive electrode, andpressure male molds 3004 and 3005 for improving a degree of contactbetween the probes 3002 and 3003 and the solid electrolyte layer 101.

Using such an ion conductivity measuring cell, the ion conductivity ismeasured as follows. First, the solid electrolyte layer is inserted intothe cylindrical hole of the circular cylinder 3001. Next, the probes3002 and 3003 are inserted into the cylindrical hole from both sides ofthe solid electrolyte layer, and then the pressure male molds 3004 and3005 are inserted into the cylindrical hole from the opposite side ofthe probes 3002 and 3003 from the solid electrolyte layer.

Thereafter, four clamping bolts 3006 are passed through fourthrough-halls each formed in the pressure male molds 3004 and 3005, andthen the clamping bolts 3006 are clamped using four wing nuts 3008 whilecompressing the entire of the ion conductivity measuring cell at apressure of 5 ton/cm². Next, an ion conductivity measuring apparatus iselectrically connected to leads 3009 and 3010 attached to the pressuremale molds 3004 and 3005 of the ion conductivity measuring cell.

In this state, the ion conductivity of the solid electrolyte layer ismeasured using the ion conductivity measuring apparatus.

The ion conductivity is reduced depending on increase of the amount ofthe binder contained in the solid electrolyte layer little by little.

Experimental Procedure 2

Various solid electrolyte layers can be formed in the same manner as inthe Experimental procedure 1, except that various insulating particlesother than the electrolyte particles made of the silver-ion-conductingsolid electrolyte are utilized as the second particles to be used forcarrying the binder.

In other words, in the Experimental procedure 2, various electrolytemixture materials, in which the electrolyte particles made of thesilver-ion-conducting solid electrolyte such as iodinated silvertungstate (Ag₆I₄WO₄) and the binder particles composed from theinsulating particles carrying the binder thereon are mixed with eachother, are used.

Alumina particles, silica particles and zirconia particles are preparedas the insulating particles, respectively. The binder particles areproduced using the insulating particles according to the step <1-ii>described in the above embodiment. At this time, an amount of the binderto an amount of the binder particles is about 20 wt %.

The binder particles and the electrolyte particles are mixed with eachother to prepare electrolyte mixture materials. In this regard, it is tobe noted that the amount of the binder to an amount of each electrolytemixture material is about 10 wt %.

Various solid electrolyte layers are formed using the electrolytemixture materials, and ion conductivities thereof are measured in thesame manner as in the Experimental procedure 1.

Experimental Procedure 3

A solid electrolyte layer is formed in the same manner as in theExperimental procedure 1, except that the electrolyte particles made ofiodinated silver tungstate (Ag₆I₄WO₄) are changed to electrolyteparticles made of iodinated silver molybdate (Ag₆I₄MoO₄).

And, ion conductivity thereof is measured in the same manner as in theExperimental procedure 1.

Experimental Procedure 4

Although the styrene-butadiene-styrene block copolymer (SBR) is used asthe binder in the Experimental procedure 1, another organic polymers canbe used as the binder in this Experimental procedure 4.

Namely, solid electrolyte layers are formed in the same manner as in theExperimental procedure 1, except that the binder is changed from thestyrene-butadiene-styrene block copolymer (SBR) to another organicpolymer.

Specifically, as the organic polymers other than thestyrene-butadiene-styrene block copolymer, styrene-isoprene-styreneblock copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer(SEBS) and hot-melt resin can be used, respectively.

Various binder particles are produced using the above organic polymers,and toluene as an organic solvent to be utilized for dissolving theorganic polymers according to the steps <1-i> and <1-ii> described inthe above embodiment.

Thereafter, various electrolyte mixture materials are prepared using thethus produced binder particles.

Various solid electrolyte layers are formed using the electrolytemixture materials, and ion conductivities thereof are measured in thesame manner as in the Experimental procedure 1.

Experimental Procedure 5

Solid electrolyte layers are formed in the same manner as in theExperimental procedure 1, except that the solid electrolyte is changedfrom the silver-ion-conducting solid electrolyte to alithium-ion-conducting solid electrolyte.

Specifically, as the lithium-ion-conducting solid electrolyte,Li₂S—SiS₂—B₂S₃—LiI, Li₂S—SiS₂—P₂S₅—LiI, Li₂S—P₂S₅—GeS₂ andLi₂S—SiS₂—Li₃PO₄ each being a sulfide-based lithium-ion-conducting solidelectrolyte can be used, respectively.

In this regard, the lithium-ion-conducting solid electrolyte isdifferent from the silver-ion-conducting solid electrolyte used in theExperimental procedure 1, and it is very sensitive to moisture andeasily degraded.

Therefore, in the case where the binder solution is prepared, theelectrolyte mixture material is prepared using the binder solution, andthe solid electrolyte layer is formed using the electrolyte mixturematerial, it must pay enough attention to remove the moisture from thematerials to be used, and to prevent moisture of outside air from beingmixed with the materials to be used. For these reasons, the materialsare handled in the inside of a dry box set to inert atmosphere.

In this regard, it is to be noted that an amount of the binder to anamount of each of the electrolyte mixture materials is about 8 wt %.Thereafter, various solid electrolyte layers are formed using theelectrolyte mixture materials, and ion conductivities thereof aremeasured using the similar ion conductivity measuring apparatus asemployed in the Experimental procedure 1.

Experimental Procedure 6

In this Experimental procedure 6, a silver-ion-conducting all-solidsecondary battery is manufactured as an all-solid secondary battery inwhich the electrochemical device related to the present invention isused.

When manufacturing the silver-ion-conducting all-solid secondarybattery, the electrolyte mixture material prepared in the Experimentalprocedure 1 is utilized as an electrolyte mixture material to be usedfor forming a solid electrolyte layer. In this regard, it is to be notedthat the electrode mixture material having the appropriate amount of thestyrene-butadiene-styrene block copolymer of (typically, 8 wt %) to theamount thereof is utilized.

On the other hand, an electrode mixture material to be used for formingelectrode layers is prepared as follows. Specifically, first, δ-typesilver vanadate (δ-Ag_(0.7)V₂O₅) particles is prepared as electrodeactive material particles, iodinated silver tungstate (Ag₆I₄WO₄)particles are prepared as electrolyte particles, and iodinated silvertungstate (Ag₆I₄WO₄) particles each carrying styrene-butadiene-styreneblock copolymer (SBR) in an appropriate weight ratio (for example, 20 wt%) are prepared as binder particles, respectively.

Next, the δ-type silver vanadate particles and the iodinated silvertungstate particles are mixed with each other in an appropriate weightratio (typically, 6:4), and then the iodinated silver tungstate(Ag₆I₄WO₄) particles each carrying the styrene-butadiene-styrene blockcopolymer are added to the same.

Thereafter, these particles are sufficiently mixed with each other andcrushed to thereby obtain the electrode mixture material.

Using the electrolyte mixture material and the electrode mixturematerial, a coin type all-solid secondary battery shown in FIG. 4 ismanufactured. As shown in FIG. 4, a battery device is configured byinterposing a solid electrolyte layer 5 between a cathode layer 3 and ananode layer 4.

In the battery device, the cathode layer 3 and the anode layer 4 areformed using the above mentioned electrode mixture material. Therefore,the cathode layer 3 and the anode layer 4 have the same electrodemixture material composition. Further, each of the cathode layer 3 andthe anode layer 4 is formed from the same electrode layer 603 having adisk shape and a structure [G] shown in FIG. 3.

In this regard, a cathode collector, in which a cathode expanded mesh6031 and a cathode lead board 6032 are joined together, is buried in thecathode layer 3, and an anode collector, in which an anode expanded mesh6041 and an anode lead board 6042 are joined together, is buried in theanode layer 4.

The battery device is manufactured according to the step <c>, that is,the battery device manufacturing step 30 described in the aboveembodiment.

First, as shown in the right side of FIG. 3, molds including a femalemold having an internal diameter (typically, 10 mm) and an externaldiameter (typically, 30 mm) are prepared as molds to be used for formingan electrode layer.

Next, the cathode layer 3 and the anode layer 4 are formed using thethus prepared molds and the above prepared electrode mixture material.As the cathode layer 3 and the anode layer 4, the electrode layers 603each having a disk shape with a diameter (typically, 10 mm) and athickness (typically, 0.5 mm) and a structure [G] shown in FIG. 3 areformed.

Next, as shown in the right side of FIG. 6, a female mold 1003 to beused for forming a battery device is prepared. In this regard, thefemale mold 1003 has an external diameter and a cylindrical hole 1005with an internal diameter. One male mold 4006 having a protrusionportion 4007 with a diameter (typically, 10.0 mm) and a thickness(typically, 0.5 mm) is inserted into the cylindrical hole 1005 of thefemale mold 1003 as a lower mold.

In this state, the electrolyte mixture material 1000 is filled in thecylindrical hole 1005, a top surface of a layer formed of theelectrolyte mixture material 1000 was leveled, the other male mold 4006is inserted into the cylindrical hole 1005 as an upper mold, and thenthe two male molds 4006 are lightly pressed so that the electrolytemixture material 1000 is molded, to thereby obtain a solid electrolytelayer 104 having a structure [D] shown in FIG. 1.

Thereafter, the other male mold 4006 is removed from the cylindricalhole 1005, and the cathode layer 3 formed in advance, in which thecathode collector obtained by joining the cathode lead board and thecathode expanded mesh is buried, is inserted into one of recess portionsformed on both of surfaces of the solid electrolyte layer 104.

Next, a male mold 1004 having no protrusion portion is inserted into thecylindrical hole 1005, and then this male mold 1004 and the one malemold 4006 are lightly pressed, to thereby obtain a solid electrolytelayer 5 (104) having a structure [IV] shown in FIG. 6.

At this time, a molding pressure is preferably set to 3 ton/cm² or less.By doing so, it is possible to firmly join the anode layer and the solidelectrolyte layer together in the subsequent step.

Subsequently, the female mold 1003 is turned over so that the otherrecess portion formed on the surface of the solid electrolyte layer 104,into which any member is not inserted, is positioned at an upper side.Then, the one male mold 4006 is removed from the cylindrical hole 1005,and the anode layer 4 formed in advance is inserted into the otherrecess portion.

Next, a male mold 1004 having no protrusion portion is inserted into thecylindrical hole 1005, and then the two male molds 1004 are pressed. Inthis way, a battery device 2 having a structure [V] shown in FIG. 6, inwhich the solid electrolyte layer 5 (104) is interposed between thecathode layer 3 and the anode layer 4, is manufactured.

At this time, a molding pressure was preferably set to 4 to 5 ton/cm² orless. By doing so, the cathode layer 3, the anode layer 4 and the solidelectrolyte layer 5 (104) are firmly joined together.

Next, as shown in FIG. 4, a cathode lead board 6032 and an anode leadboard 6042 are, respectively, attached to the cathode layer 3 and theanode layer 4 of the manufactured battery device 2. Thereafter, almostall of the battery device other than the cathode lead board 6032 and theanode lead board 6042 is covered with a hot-melt resin, and then it iscured.

A cured product of such a hot-melt resin would serve as a restrictor6080 being able to suppress expansion and contraction of volumes of thecathode layer 3 and the anode layer 4 due to structural changes ofcrystals of the electrode active material when the battery device 2 isin charge-discharge operation.

The obtained battery device 2 with the restrictor 6080 is inserted intoa container body 90 of a battery container 9. Thermosetting epoxy powderis filled into a space formed within the container body 90, and then atop opening of the container body 90 is closed by a lid 91 through aninsulating packing agent 17 while pressing the lid 91 against thecontainer body 90.

Thereafter, the thermosetting epoxy powder filled into the space isheated together with the battery device 2 with the restrictor 6080 andthe battery container 9 and cured. In this way, thesilver-ion-conducting all-solid secondary battery shown in FIG. 4 isobtained.

Thereafter, an initial charge-discharge property and a property of adischarge voltage against a discharge current density of the thusobtained all-solid secondary battery are checked.

As the initial charge-discharge property, initial charge-dischargebehavior was checked by charging the all-solid secondary battery up to0.52 V at a current density of 0.1 mAh/cm², stopping charge operation atthe moment when an electrical current became equal to 20 μA, and thendischarging it at a current density of 0.1 mAh/cm².

On the other hand, as the property of the discharge voltage against thedischarge current density, a terminal voltage of the all-solid secondarybattery is checked at the moment when a discharge capacity thereofbecomes equal to 10.0 mAh/gr against the used electrode active materialby discharging it at a current density of 0.1, 0.2, 0.4, 0.6 or 1.0mAh/cm² after it is charged in the same manner as described above.

Experimental Procedure 7

In the Experimental procedure 6, the electrolyte particles made of thesilver-ion-conducting solid electrolyte and carrying the binder areutilized as the binder particles to be used for preparing theelectrolyte mixture material.

On the other hand, in this Experimental procedure 7, various all-solidsecondary batteries are manufactured in the same manner as in theExperimental procedure 6, except that alumina particles, silicaparticles and zirconia particles are, respectively, used as the secondparticles to be used for carrying the binder and the binder particles tobe used for preparing the electrolyte mixture material are produced bycarrying the binder on surfaces of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 8

In the Experimental procedure 6, the electrolyte particles made of thesilver-ion-conducting solid electrolyte and carrying the binder areutilized as the binder particles to be used for preparing the electrodemixture material.

On the other hand, in this Experimental procedure 8, various all-solidsecondary batteries are manufactured in a similar manner as in theExperimental procedure 6, except that alumina particles, silicaparticles and zirconia particles are, respectively, used as the secondparticles to be used for carrying the binder and the binder particles tobe used for preparing the electrode mixture material are produced bycarrying the binder on surfaces of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 9

In the Experimental procedure 6, the electrolyte particles made of thesilver-ion-conducting solid electrolyte and carrying the binder areutilized as the binder particles to be used for preparing the electrodemixture material.

On the other hand, in this Experimental procedure 9, various all-solidsecondary batteries are manufactured in the same manner as in theExperimental procedure 6, except that graphite particles, acetyleneblack particles each having a particle size (typically, 20 micrometers)and silver particles each having a particle size (typically, 15micrometers) are, respectively, used as the second particles to be usedfor carrying the binder and the binder particles to be used forpreparing the electrode mixture material are produced by carrying thebinder on surfaces of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 10

In this Experimental procedure 10, a sulfide-basedlithium-ion-conducting all-solid secondary battery, including a cathodelayer, an anode layer and a solid electrolyte layer each having a squareshape, is manufactured as an all-solid secondary battery in which theelectrochemical device related to the present invention is used.

When manufacturing the sulfide-based lithium-ion-conducting all-solidsecondary battery, as molds to be used for forming the cathode and anodelayers, a female mold and two male molds each corresponding to thefemale mold are prepared.

Further, as molds to be used for manufacturing the battery device (thesolid electrolyte layer), a female mold and two male molds eachcorresponding to the female mold and a protrusion portion are prepared.

In this regard, it is to be noted that the protrusion portion is usedfor forming a recess portion at a central portion of the solidelectrolyte layer. The sulfide-based lithium-ion-conducting all-solidsecondary battery is manufactured using the above molds in the samemanner as in the Experimental procedure 6.

In this Experimental procedure 10, the electrolyte mixture materialprepared in the Experimental procedure 5 is used as an electrolytemixture material. Namely, the electrolyte mixture material contained theelectrolyte particles made of the Li₂S—SiS₂—Li₃PO₄ which is an amorphoussulfide-based lithium-ion-conducting solid electrolyte (an amorphoussulfide-based lithium-ion conductor).

Further, a cathode mixture material to be used for forming a cathodelayer is prepared as follows. Specifically, first, lithium cobaltate(Li_(x)CoO₂) particles are prepared as cathode active materialparticles, Li₂S—SiS₂—Li₃PO₄ (ternary amorphous lithium-ion-conductingsolid electrolyte consisting of lithium sulfide, silicon sulfide andlithium phosphate) particles were prepared as electrolyte particles, andLi₂S—SiS₂—Li₃PO₄ particles each having a particle size (typically, 15micrometers) or less and carrying styrene-butadiene-styrene blockcopolymer (SBR) in an appropriate weight ratio (typically, 20 wt %) areprepared as binder particles, respectively.

Next, the lithium cobaltate particles and the Li₂S—SiS₂—Li₃PO₄ particlesare mixed with each other in a weight ratio (typically, 8:2), and thenthe Li₂S—SiS₂—Li₃PO₄ particles each carrying thestyrene-butadiene-styrene block copolymer are added to the same.

Thereafter, these particles are sufficiently mixed with each other andcrushed to thereby obtain the cathode mixture material.

On the other hand, an anode mixture material to be used for forming ananode layer is prepared as follows. Specifically, first, metallic indiumparticles each having a particle size (typically, 10 micrometers) areprepared as anode active material particles, Li₂S—SiS₂—Li₃PO₄ (ternaryamorphous lithium-ion-conducting solid electrolyte consisting of lithiumsulfide, silicon sulfide and lithium phosphate) particles are preparedas electrolyte particles, and Li₂S—SiS₂—Li₃PO₄ particles each having aparticle size of about 15 micrometers or less and carryingstyrene-butadiene-styrene block copolymer (SBR) in an appropriate weightratio (typically, 20 wt %) are prepared as binder particles,respectively.

Next, the metallic indium particles and the Li₂S—SiS₂—Li₃PO₄ particlesare mixed with each other in a weight ratio (typically, 6:4), and thenthe Li₂S—SiS₂—Li₃PO₄ particles each carrying thestyrene-butadiene-styrene block copolymer are added to the same.

Thereafter, these particles are sufficiently mixed with each other andcrushed to thereby obtain the anode mixture material.

Further, a copper expanded mesh having a thickness (typically, 70micrometers) and an occupation percentage of through-holes (typically,75%) is prepared for forming an anode collector, and a copper expandedmesh having a thickness (typically, 70 micrometers) and an occupationpercentage of through-holes (typically, 75%), on which titanium isdeposited, is prepared for forming a cathode collector.

Furthermore, a copper foil having a thickness (typically, 50micrometers) is prepared as an anode lead board to be used for formingthe anode collector, and a copper foil having a thickness (typically, 50micrometers), on which titanium is deposited, is prepared as a cathodelead board to be used for forming the cathode collector.

Subsequently, the copper expanded mesh and the copper foil are weldedand fixed together at a plurality of points using a spot welding, andthen they are cut to a required size having a length (typically, 15 mm)and a width (typically, 15 mm), to thereby obtain the anode collector.

Likewise, the titanium deposited copper expanded mesh and the titaniumdeposited copper foil are welded and fixed together at a plurality ofpoints using a spot welding, and then they are cut to a required sizehaving a length (typically, 15 mm) and a width (typically, 15 mm), tothereby obtain the cathode collector.

In advance, cathode and anode layers are formed using the cathode andanode mixture materials, the cathode and anode collectors and the moldsto be used for forming the cathode and anode layers.

Next, using the thus formed cathode and anode layers and the aboveprepared molds to be used for manufacturing the battery device, anall-solid secondary battery having a square shape, as shown in FIG. 5,is manufactured according to the flowchart illustrating the method formanufacturing the all-solid secondary battery shown in FIG. 9.

Further, as shown in FIG. 5, the all-solid secondary battery is providedwith a battery device in which the solid electrolyte layer is positionedbetween the cathode layer and the anode layer, and peripheral portionsof the cathode and anode layers are covered with the solid electrolytelayer.

Thereafter, an initial charge-discharge property and a property of adischarge voltage against a discharge current density of the thusobtained all-solid secondary battery are checked.

Experimental Procedure 11

In the Experimental procedure 10, the electrolyte particles made of theternary lithium-ion-conducting solid electrolyte (i.e.,Li₂S—SiS₂—Li₃PO₄) and carrying the binder are utilized as the binderparticles to be used for preparing the electrolyte mixture material.

On the other hand, in this Experimental procedure 11, various secondarybatteries are manufactured in the same manner as in the Experimentalprocedure 10, except that alumina particles, silica particles andzirconia particles were, respectively, used as the second particles tobe used for carrying the binder, and the binder particles to be used forpreparing the electrolyte mixture material are produced by carrying thebinder on surface of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 12

In the Experimental procedure 10, the electrolyte particles made of theternary lithium-ion-conducting solid electrolyte (i.e.,Li₂S—SiS₂—Li₃PO₄) and carrying the binder are utilized as the binderparticles to be used for preparing the electrode mixture material.

On the other hand, in this Experimental procedure 12, various all-solidsecondary batteries are manufactured in the same manner as in theExperimental procedure 10, except that alumina particles, silicaparticles and zirconia particles are, respectively, used as the secondparticles to be used for carrying the binder, and the binder particlesto be used for preparing the electrode mixture material are produced bycarrying the binder on surfaces of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 13

In the Experimental procedure 10, the electrolyte particles made of theternary lithium-ion-conducting solid electrolyte (i.e.,Li₂S—SiS₂—Li₃PO₄) and carrying the binder are utilized as the binderparticles to be used for preparing the electrode mixture material.

On the other hand, in this Experimental procedure 13, various all-solidsecondary batteries are manufactured in the same manner as in theExperimental procedure 10, except that graphite particles, acetyleneblack particles each having a particle size (typically, 20 micrometers)and silver particles each having a particle size (typically, 20micrometers) are, respectively, used as the second particles to be usedfor carrying the binder, and the binder particles to be used forpreparing the electrode mixture material are produced by carrying thebinder on surfaces of the above particles.

Thereafter, a discharge property of each of the thus manufacturedall-solid secondary batteries is checked.

Experimental Procedure 14

In the Experimental procedure 10, the sulfide-basedlithium-ion-conducting all-solid secondary battery is manufactured usingthe ternary lithium-ion-conducting solid electrolyte (i.e.,Li₂S—SiS₂—Li₃PO₄) as an all-solid secondary battery in which theelectrochemical device of the present invention is used.

On the other hand, in this Experimental procedure 14, alithium-ion-conducting all-solid secondary battery was manufactured inthe same manner in the Experimental procedure 10 except that the ternarylithium-ion-conducting solid electrolyte is changed from theLi₂S—SiS₂—Li₃PO₄. to Li₂S—P₂S₅—GeS₂ (i.e., thio-silicon).

Namely, in this Experimental procedure 14, the electrolyte mixturematerial prepared in the Experimental procedure 5 is used as anelectrolyte mixture material. Namely, the electrolyte mixture materialcontained the electrolyte particles made of the Li₂S—P₂S₅—GeS₂ which isa crystalline sulfide-based lithium-ion-conducting solid electrolyte.

Further, a cathode mixture material to be used for forming a cathodelayer is prepared as follows. Specifically, first, lithium cobaltate(Li_(x)CoO₂) particles are prepared as cathode active materialparticles, Li₂S—P₂S₅—GeS₂ (ternary crystalline lithium-ion-conductingsolid electrolyte) particles were prepared as electrolyte particles, andLi₂S—P₂S₅—GeS₂ particles each having a particle size of about 15micrometers or less and carrying styrene-butadiene-styrene blockcopolymer (SBR) in a weight ratio (typically, 20 wt %) are prepared asbinder particles, respectively.

Next, the lithium cobaltate particles and the Li₂S—P₂S₅—GeS₂ particleswere mixed with each other in a weight ratio (typically, 8:2), and thenthe Li₂S—P₂S₅—GeS₂ particles each carrying the styrene-butadiene-styreneblock copolymer are added to the same.

Thereafter, these particles are sufficiently mixed with each other andcrushed to thereby obtain the cathode mixture material.

On the other hand, an anode mixture material to be used for forming ananode layer is prepared as follows. Specifically, first, metallic indiumparticles each having a particle size (typically, 10 micrometers) areprepared as anode active material particles, Li₂S—P₂S₅—GeS₂ (ternarycrystalline lithium-ion-conducting solid electrolyte) particles areprepared as electrolyte particles, and Li₂S—P₂S₅—GeS₂ particles eachhaving a particle size of about 15 micrometers or less and carryingstyrene-butadiene-styrene block copolymer (SBR) in a weight ratio(typically, 20 wt %) are prepared as binder particles, respectively.

Next, the metallic indium particles and the Li₂S—P₂S₅—GeS₂ particles aremixed with each other in a weight ratio (typically, 6:4), and then theLi₂S—P₂S₅—GeS₂ particles each carrying the styrene-butadiene-styreneblock copolymer are added to the same.

Thereafter, these particles are sufficiently mixed with each other andcrushed to thereby obtain an anode mixture material.

Further, a copper expanded mesh having a thickness (typically, 70micrometers) and an occupation percentage (typically, through-holes of75%) is prepared for forming an anode collector, and a copper expandedmesh having a thickness (typically, 70 micrometers) and an occupationpercentage of through-holes (typically, 75%), on which titanium isdeposited, is prepared for forming a cathode collector.

Furthermore, a copper foil having a thickness (typically, 50micrometers) is prepared as an anode lead board to be used for formingthe anode collector, and a copper foil having a thickness (typically, 50micrometers), on which titanium is deposited, is prepared as a cathodelead board to be used for forming the cathode collector.

Subsequently, the copper expanded mesh and the copper foil are weldedand fixed together at a plurality of points using a spot welding, andthen they are cut to a required size having a length (typically, 15 mm)and a width (typically, 15 mm), to thereby obtain the anode collector.

Likewise, the titanium deposited copper expanded mesh and the titaniumdeposited copper foil are welded and fixed together at a plurality ofpoints using a spot welding, and then they are cut to a required sizehaving a length (typically, 15 mm) and a width (typically, 15 mm), tothereby obtain the cathode collector.

In advance, cathode and anode layers are formed using the cathode andanode mixture materials, the cathode and anode collectors and the moldsto be used for forming the cathode and anode layers.

Next, using the thus formed cathode and anode layers and the aboveprepared molds to be used for manufacturing the battery device, anall-solid secondary battery having a square shape, as shown in FIG. 5,is manufactured according to the flowchart illustrating the method formanufacturing the all-solid secondary battery shown in FIG. 9.

Further, as shown in FIG. 5, the all-solid secondary battery is providedwith a battery device in which a solid electrolyte layer is positionedbetween the cathode layer and the anode layer, and peripheral portionsof the cathode and anode layers are covered with the solid electrolytelayer.

Hereinbefore, in the all-solid secondary battery manufactured in thisway, the battery device is configured by interposing the solidelectrolyte layer 5 between the cathode layer 3 and the anode layer 4.

Further, the cathode extraction lead 6034 and the anode extraction lead6044 each having electrical conductivity are, respectively, connected tothe cathode layer 3 and the anode layer 4, and serve as lead linesthrough which electricity is charged to and discharged from the batterydevice.

In the all-solid secondary battery, almost all of the battery deviceother than the cathode extraction lead 6034 and the anode extractionlead 6044 is covered with the restrictor 6080, thus allowing the cathodeextraction lead 6034 and the anode extraction lead 6044 to be exposed tothe outside.

The restrictor 6080 serves mainly to restrict expansion of each of thecathode layer 3 and the anode layer 4 in a plane direction thereof (in adirection generally perpendicular to a direction crossing the cathodelayer 3 and the anode layer 4) and the resultant expansion of the solidelectrolyte layer 5 in a plane direction thereof.

In the battery device (the all-solid secondary battery), crystalstructures of the electrode active material contained in the cathodelayer 3 and the anode layer 4 are three-dimensionally deformed (expandedor contracted) in response to charge-discharge operations thereof.

In a hypothetical case that the all-solid secondary battery is notprovided with the restrictor 6080, the cathode layer 3 and the anodelayer 4 are heavily deformed (expanded or contracted) in the planedirection thereof but not in a thickness direction thereof as thecrystal structures of the electrode active material arethree-dimensionally deformed or changed.

As a result, especially in peripheral portions of the cathode layer 3and the anode layer 4, a bond inhibition phenomenon that breaks ordisconnects an electronic bond or an ion-conducting path is created.This makes it difficult for an electric current to flow through theperipheral portions of the cathode layer 3 and the anode layer 4 whencharging or discharging the battery device.

Further, at this time, the solid electrolyte layer 5 is also deformed(expanded or contracted) in the plane direction thereof due to theexpansion or contraction of the cathode layer 3 and the anode layer 4 inthe plane direction thereof, thereby forming a protruding portion thatprotrudes from the cathode layer 3 and the anode layer 4. In theprotruding portion the ion-conducting path is broken.

This phenomenon proceeds gradually as the battery device included in theall-solid secondary battery is repeatedly charged and discharged. As aconsequence, a battery capacity of the battery device is graduallyreduced, which makes it difficult to charge and discharge the all-solidsecondary battery.

In contrast, the all-solid secondary battery of the above embodiment isconfigured to have the restrictor 6080 that serves to restrict expansionof each of the cathode layer 3 and the anode layer 4 in the planedirection thereof and the resultant expansion of the solid electrolytelayer 5 in the plane direction thereof. Thus, the battery device can bekept in a shape as close to an initial shape as possible whenmanufacturing the all-solid secondary battery and charging anddischarging the same.

That is to say, the afore-mentioned problem can be avoided byrestricting expansion of the cathode layer 3, the anode layer 4 and thesolid electrolyte layer 5 in the plane direction thereof. As a result,it becomes possible to avoid battery capacity reduction which wouldotherwise occur over a lapse of charge-discharge cycles (by multipletimes of charge-discharge operations).

The restrictor 6080 is preferably made of an insulating material. Thishelps to reliably prevent short-circuit between the cathode layer 3 andthe anode layer 4.

Alternatively, the restrictor 6080 may be made of a conducting material(e.g., metallic material or the like). In this case, it is prepared thatan insulating layer (an insulating sheet) is interposed between thebattery device and the restrictor 6080.

Examples of the insulating material include various kinds of resinmaterials such as a thermoplastic resin, a thermosetting resin and aphotocurable resin, various kinds of glass materials and various kindsof ceramics materials.

Among these materials, it is desirable that the insulating material ismainly any one of a thermoplastic resin, a thermosetting resin, aphotocurable resin and a low-melting-point glass or a combination of twoor more of them. Use of these materials allows the restrictor 6080 to beformed with ease. Furthermore, use of these materials helps to increasemechanical strength of the restrictor 6080.

Examples of the thermoplastic resin include polyolefin, ethylene-vinylacetate copolymer, polyamide, polyimide, hot-melt resin and the like.Examples of the thermosetting resin include epoxy-based resin,polyurethane-based resin, phenol-based resin and the like.

Further, examples of the photocurable resin include epoxy-based resin,urethane acrylate-based resin, vinyl ether-based resin and the like.Examples of the low-melting-point glass include P₂O₅—CuO—ZnO-basedlow-melting-point glass, P₂O₅—SnO-based low-melting-point glass,B₂O₃—ZnO—Bi₂O₃—Al₂O₃-based low-melting-point glass and the like.

An average thickness of the restrictor 6080 (particularly, an averagethickness of an end portion thereof) is preferably about in the range of50 to 5000 μm, and more preferably in the range of about 100 to 500 μm,although it may be slightly changed depending on the constituentmaterial and intended use of the restrictor 6080.

By setting the average thickness within this range, it is possible toreliably prevent expansion of each of the cathode layer 3, the anodelayer 4 and the solid electrolyte layer 5 in the plane directionthereof, thereby allowing the restrictor 6080 to play its role in areliable manner.

In this regard, it is to be noted that in the case where the fixedportion 6090 shown in each of FIGS. 4 and 5 is made of the same materialas the constituent material of the restrictor 6080, the restrictor 6080may be omitted from the all-solid secondary battery.

As described above, the battery container 9 can receive the batterydevice with the restrictor 6080 and has a function of protecting thebattery device from external impact or the like.

Further, the battery container 9 includes the container body 90 havingthe bottom-closed hollow cylindrical shape and the lid 91 for closingthe top opening of the container body 91. The battery device with therestrictor 6080 are fixed in the inside of the container body 90 throughthe fixed portion 6090.

Furthermore, as shown in FIG. 5, the cathode extraction lead 6034 andthe anode extraction lead 6044 are inserted through the lid 91 and fixedor attached to the lid 91 by way of the insulating tubes 93 so that theycan be kept free from short-circuit.

Examples of a constituent material of the battery container 9 (thecontainer body 90 and the lid 91) include various kinds of metallicmaterials such as aluminum, copper, brass and stainless steel, variouskinds of resin materials, various kinds of ceramics materials, variouskinds of glass materials, various kinds of composite materialscomprising the metal material and the resin material and the like, andone or more kind of which may be used independently or in combination.

Further, examples of a constituent material of the fixed portion 6090include curable resins such as a thermosetting resin and a photocurableresin, a thermoplastic resin and a low-melting-point glass eachmentioned as the restrictor 6080, and the like.

In the case where the all-solid secondary battery has such a batterycontainer 9, it is possible to reliably protect the battery deviceprovided within the battery container 9 from the external impact or thelike thereof, and to reliably restrict expansion of each of the cathodelayer 3, the anode layer 4 and the solid electrolyte layer 5 in theplane direction thereof.

In addition, such a battery structure helps to prevent infiltration ofexternal moisture into the battery device and can be suitably used inconstructing an all-solid secondary battery (particularly, alithium-ion-conducting all-secondary battery).

Hereinbefore, although the all-solid secondary battery, in which theelectrochemical device according to the present invention is used, havebeen described based on the embodiments illustrated in the drawings, thepresent invention is not limited thereto.

The solid electrolyte layer formed using the electrolyte mixturematerial described above has more excellent ion conductivity as comparedto a solid electrolyte layer formed using a conventional electrolytemixture material.

Further, the electrode layer formed using the electrode mixture materialdescribed above has a more superior ion-conducting path therein ascompared to an electrode layer formed using a conventional electrodemixture material.

Therefore, it is believed that various kinds of electrochemicalapparatuses, in which the electrochemical device having such a solidelectrolyte layer and/or such an electrode layer is provided, canexhibit excellent properties.

For example, in the case where the solid electrolyte layer is made ofthe silver-ion-conducting solid electrolyte and the cathode layer andthe anode layer are, respectively, made of silver and stainless steel(SUS), the electrochemical device can be used as an electrical chargecensor. Therefore, an electrochemical timer can be easily constitutedfrom such an electrical charge censor.

Further, the battery device having the structure described in theExperimental procedure 1 can be used as an electrochemical actuator byutilizing the volume change of the electrode active material whenelectrifying between the cathode layer and the anode layer.

Furthermore, in the case where a semiconductor photoelectrode layer isprovided on one layer of the cathode and anode layers of the batterydevice having the structure described in the Experimental procedure 1,such a battery device can be used as a photosensitive secondary batterywhich can be charged by means of light.

Moreover, in the case where an electrochromic layer made of anelectrochromic material is provided on one layer of the cathode andanode layers of the battery device having the structure described in theExperimental procedure 1, such a battery device can be used as anelectrochromic display apparatus.

As described above, the electrochemical device according to the presentinvention can be used for constructing not only the above all-solidsecondary battery but also various kinds of electrochemical apparatuses.

EXAMPLES Example 1

In this example 1, a solid electrolyte layer using electrolyte particles(first particles) made of a silver-ion-conducting solid electrolyte (asilver-ion conductor) will be described.

Iodinated silver tungstate (Ag₆I₄WO₄) was used as thesilver-ion-conducting solid electrolyte. The iodinated silver tungstatewas received into an alumina pot and crushed using a planet ball millingmachine with alumina balls to obtain a crushed matter.

This crushed matter was screened to obtain particles. Particles having aparticle size of about 15 micrometers or less were utilized as theelectrolyte particles (the first particles) to be used for forming thesolid electrolyte layer.

On the other hand, particles having a particles size of about 15micrometers or more were utilized as second particles to be used forcarrying a binder composed of an organic polymer (that is, secondparticles to be used for producing binder particles).

Prior to producing the binder particles, first,styrene-butadiene-styrene block copolymer (SBR) was prepared as theorganic polymer consisting the binder, toluene was prepared as anorganic solvent to be used for dissolving the binder, and then they weremixed with each other to thereby obtain a toluene solution containingthe styrene-butadiene-styrene block copolymer at a concentration of 30wt %.

Next, this toluene solution (binder solution or polymer solution) andthe electrolyte particles (the second particles) to be used for carryingthe binder were sufficiently mixed with each other to obtain a mixturesolution, the toluene was evaporated and removed from the mixturesolution to obtain a solid matter, and then the solid matter was crushedusing a freeze crusher in the size of about 20 micrometers or less. Inthis way, the binder particles to be used for forming the electrolytelayer were obtained.

Subsequently, the electrolyte particles and the binder particles weremixed with each other in various ratios to prepare electrolyte mixturematerials. Each of the electrolyte mixture materials was formed in theform of a disk having a diameter of 10 mm according to the method offorming the solid electrolyte layer described in the above embodiment,to thereby obtain various solid electrolyte layers each having astructure [A] shown in FIG. 1 and a different amount of the binder.

Ion conductivity was measured for each of the thus obtained solidelectrolyte layers using an ion conductivity measuring cell shown inFIG. 7.

As shown in FIG. 7, the ion conductivity measuring cell included acircular cylinder 3001 made of PET with an external diameter of 35 mmand having a cylindrical hole with an internal diameter of 10 mm, probes3002 and 3003 each made of SUS and being to be inserted into an one endof the cylindrical hole as an electrochemically inactive electrode, andpressure male molds 3004 and 3005 for improving a degree of contactbetween the probes 3002 and 3003 and the solid electrolyte layer 101.

Using such an ion conductivity measuring cell, the ion conductivity wasmeasured as follows. First, the solid electrolyte layer was insertedinto the cylindrical hole of the circular cylinder 3001. Next, theprobes 3002 and 3003 were inserted into the cylindrical hole from bothsides of the solid electrolyte layer, and then the pressure male molds3004 and 3005 were inserted into the cylindrical hole from the oppositeside of the probes 3002 and 3003 from the solid electrolyte layer.

Thereafter, four clamping bolts 3006 were passed through fourthrough-halls each formed in the pressure male molds 3004 and 3005, andthen the clamping bolts 3006 were clamped using four wing nuts 3008while compressing the entire of the ion conductivity measuring cell at apressure of 5 ton/cm². Next, an ion conductivity measuring apparatus waselectrically connected to leads 3009 and 3010 attached to the pressuremale molds 3004 and 3005 of the ion conductivity measuring cell.

In this state, the ion conductivity of the solid electrolyte layer wasmeasured using the ion conductivity measuring apparatus.

A value of the ion conductivity of each of the solid electrolyte layersis shown with a symbol “o” in FIG. 8. As is apparent from these results,the ion conductivity of the solid electrolyte layer containing no binderwas about 2.5×10⁻² S/cm, but the ion conductivity was reduced dependingon increase of the amount of the binder contained in the solidelectrolyte layer little by little.

The ion conductivity of the solid electrolyte layer having the amount ofthe binder of 20 wt % or more was about 1.1×10⁻⁴ S/cm, which was lowerthan a value that required for a practical all-solid secondary battery,that is, 4×10⁻⁴ S/cm.

Comparative Example 1

In order to confirm an effect in the Example 1, an organic solvent(toluene) was added to the same electrolyte mixture materials asprepared in the Example 1 so that the binders contained therein weredissolved in the organic solvent to obtain various slurries, the organicsolvent was evaporated and removed from the slurries to obtain solidmatters, and then the solid matters were crushed using a planet ballmilling machine in the size of about 20 micrometers or less, to therebyobtain crushed matters. These crushed matters were used as electrolytemixture materials, respectively.

Various solid electrolyte layers each having a different amount of thebinder were formed using these electrolyte mixture materials, and ionconductivities thereof were measured in the same manner as in theExample 1.

A value of the ion conductivity of each of the solid electrolyte layersis shown with a symbol “●” in FIG. 8. As is apparent from these results,in the case where each of the solid electrolyte layers containedelectrolyte particles all covered with the binder, the ion conductivitythereof was exponentially reduced depending on increase of the amount ofthe binder contained in the solid electrolyte layer.

Example 2

Although the styrene-butadiene-styrene block copolymer (SBR) was used asthe binder in the Example 1, another organic polymers were used as thebinder in this Example 2.

Namely, solid electrolyte layers were formed in the same manner as inthe Example 1, except that the binder was changed from thestyrene-butadiene-styrene block copolymer (SBR) to another organicpolymers.

Specifically, as the organic polymers other than thestyrene-butadiene-styrene block copolymer, styrene-isoprene-styreneblock copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer(SEBS) and hot-melt resin were used, respectively.

Various binder particles were produced using the above organic polymers,and toluene as an organic solvent to be utilized for dissolving theorganic polymers according to the steps <1-i> and <1-ii> described inthe above embodiment.

Thereafter, various electrolyte mixture materials were prepared usingthe thus produced binder particles. In this regard, it is to be notedthat an amount of the binder to an amount of each of the electrolytemixture materials was 7 wt %.

Various solid electrolyte layers were formed using the electrolytemixture materials, and ion conductivities thereof were measured in thesame manner as in the Example 1. As a result, the ion conductivities ofall of the solid electrolyte layers, which were obtained using theorganic polymers other than the styrene-butadiene-styrene blockcopolymer as the binder, were 1.2×10⁻³ S/cm or more.

These results showed that the solid electrolyte layers each formed inthe Example 2 were no less advantageous than a solid electrolyte layerformed using only the electrolyte particles and having ion conductivityof 2.5×10⁻² S/cm. Namely, an effect of the present invention could beconfirmed.

Example 3

In this Example 3, a silver-ion-conducting all-solid secondary batterywas manufactured as an all-solid secondary battery in which theelectrochemical device of the present invention was used.

When manufacturing the silver-ion-conducting all-solid secondarybattery, the electrolyte mixture material prepared in the Example 1 wasutilized as an electrolyte mixture material to be used for forming asolid electrolyte layer. In this regard, it is to be noted that theelectrode mixture material having the amount of thestyrene-butadiene-styrene block copolymer of 8 wt % to the amountthereof was utilized.

On the other hand, an electrode mixture material to be used for formingelectrode layers was prepared as follows. Specifically, first, δ-typesilver vanadate (δ-Ag_(0.7)V₂O₅) particles were prepared as electrodeactive material particles, iodinated silver tungstate (Ag₆I₄WO₄)particles were prepared as electrolyte particles, and iodinated silvertungstate (Ag₆I₄WO₄) particles each carrying styrene-butadiene-styreneblock copolymer (SBR) in a weight ratio of 20 wt % were prepared asbinder particles, respectively.

Next, the δ-type silver vanadate particles and the iodinated silvertungstate particles were mixed with each other in a weight ratio of 6:4,and then the iodinated silver tungstate (Ag₆I₄WO₄) particles eachcarrying the styrene-butadiene-styrene block copolymer were added to thesame.

Thereafter, these particles were sufficiently mixed with each other andcrushed to thereby obtain the electrode mixture material. In thisregard, it is to be noted that an amount of thestyrene-butadiene-styrene block copolymer to an amount of the electrodemixture material was 8 wt %.

Using the electrolyte mixture material and the electrode mixturematerial, a coin type all-solid secondary battery shown in FIG. 4 wasmanufactured. As shown in FIG. 4, a battery device was configured byinterposing a solid electrolyte layer 5 between a cathode layer 3 and ananode layer 4.

In the battery device, the cathode layer 3 and the anode layer 4 wereformed using the above mentioned electrode mixture material. Therefore,the cathode layer 3 and the anode layer 4 had the same electrode mixturematerial composition. Further, each of the cathode layer 3 and the anodelayer 4 was formed from the same electrode layer 603 having a disk shapeand a structure [G] shown in FIG. 3.

In this regard, a cathode collector, in which a cathode expanded mesh6031 and a cathode lead board 6032 were joined together, was buried inthe cathode layer 3, and an anode collector, in which an anode expandedmesh 6041 and an anode lead board 6042 were joined together, was buriedin the anode layer 4.

The battery device was manufactured according to the step <c>, that is,the battery device manufacturing step 30 described in the aboveembodiment.

First, as shown in the right side of FIG. 3, molds including a femalemold having an internal diameter of 10 mm and an external diameter 30 mmwere prepared as molds to be used for forming an electrode layer.

Next, the cathode layer 3 and the anode layer 4 were formed using thethus prepared molds and the above prepared electrode mixture material.As the cathode layer 3 and the anode layer 4, the electrode layers 603each having a disk shape with a diameter of 10 mm and a thickness of 0.5mm and a structure [G] shown in FIG. 3 were formed.

Next, as shown in the right side of FIG. 6, a female mold 1003 to beused for forming a battery device was prepared. In this regard, thefemale mold 1003 had an external diameter of 30 mm and a cylindricalhole 1005 with an internal diameter of 11 mm. One male mold 4006 havinga protrusion portion 4007 with a diameter of 10.4 mm and a thickness of0.5 mm was inserted into the cylindrical hole 1005 of the female mold1003 as a lower mold.

In this state, the electrolyte mixture material 1000 was filled in thecylindrical hole 1005, a top surface of a layer formed of theelectrolyte mixture material 1000 was leveled, the other male mold 4006was inserted into the cylindrical hole 1005 as an upper mold, and thenthe two male molds 4006 were lightly pressed so that the electrolytemixture material 1000 was molded, to thereby obtain a solid electrolytelayer 104 having a structure [D] shown in FIG. 1.

Thereafter, the other male mold 4006 was removed from the cylindricalhole 1005, and the cathode layer 3 formed in advance, in which thecathode collector obtained by joining the cathode lead board and thecathode expanded mesh was buried, was inserted into one of recessportions formed on both of surfaces of the solid electrolyte layer 104.

Next, a male mold 1004 having no protrusion portion was inserted intothe cylindrical hole 1005, and then this male mold 1004 and the one malemold 4006 are lightly pressed, to thereby obtain a solid electrolytelayer 5 (104) having a structure [IV] shown in FIG. 6.

At this time, a molding pressure was preferably set to 3 ton/cm² orless. By doing so, it was possible to firmly join the anode layer andthe solid electrolyte layer together in the subsequent step.

Subsequently, the female mold 1003 was turned over so that the otherrecess portion formed on the surface of the solid electrolyte layer 104,into which any member was not inserted, was positioned at an upper side.Then, the one male mold 4006 was removed from the cylindrical hole 1005,and the anode layer 4 formed in advance was inserted into the otherrecess portion.

Next, a male mold 1004 having no protrusion portion was inserted intothe cylindrical hole 1005, and then the two male molds 1004 werepressed. In this way, a battery device 2 having a structure [V] shown inFIG. 6, in which the solid electrolyte layer 5 (104) was interposedbetween the cathode layer 3 and the anode layer 4, was manufactured.

At this time, a molding pressure was preferably set to 4 to 5 ton/cm² orless. By doing so, the cathode layer 3, the anode layer 4 and the solidelectrolyte layer 5 (104) were firmly joined together.

Next, as shown in FIG. 4, a cathode lead board 6032 and an anode leadboard 6042 were, respectively, attached to the cathode layer 3 and theanode layer 4 of the manufactured battery device 2. Thereafter, almostall of the battery device other than the cathode lead board 6032 and theanode lead board 6042 was covered with a hot-melt resin, and then it wascured.

A cured product of such a hot-melt resin would serve as a restrictor6080 being able to suppress expansion and contraction of volumes of thecathode layer 3 and the anode layer 4 due to structural changes ofcrystals of the electrode active material when the battery device 2 isin charge-discharge operation.

In this regard, it is to be noted that an average thickness of therestrictor 6080 in an end portion of the battery device was 0.5 mm, andan average thickness thereof in a plane portion other than the endportion was 0.01 mm.

The thus obtained battery device 2 with the restrictor 6080 was insertedinto a container body 90 of a battery container 9. Thermosetting epoxypowder was filled into a space formed within the container body 90, andthen a top opening of the container body 90 was closed by a lid 91through an insulating packing agent 17 while pressing the lid 91 againstthe container body 90.

Thereafter, the thermosetting epoxy powder filled into the space washeated together with the battery device 2 with the restrictor 6080 andthe battery container 9 and cured. In this way, thesilver-ion-conducting all-solid secondary battery shown in FIG. 4 wasobtained.

Thereafter, an initial charge-discharge property and a property of adischarge voltage against a discharge current density of the thusobtained all-solid secondary battery were checked.

As the initial charge-discharge property, initial charge-dischargebehavior was checked by charging the all-solid secondary battery up to0.52 V at a current density of 0.1 mAh/cm², stopping charge operation atthe moment when an electrical current became equal to 20 μA, and thendischarging it at a current density of 0.1 mAh/cm².

On the other hand, as the property of the discharge voltage against thedischarge current density, a terminal voltage of the all-solid secondarybattery was checked at the moment when a discharge capacity thereofbecame equal to 10.0 mAh/gr against the used electrode active materialby discharging it at a current density of 0.1, 0.2, 0.4, 0.6 or 1.0mAh/cm² after it was charged in the same manner as described above.

In the graph of FIG. 10, the initial charge-discharge behavior of theall-solid secondary battery when charging-discharging it at a currentdensity of 0.1 mAh/cm² was shown. The all-solid secondary battery had acharge-discharge capacity of about 27 mAh/gr and a discharge voltage ofabout 0.35 V. This behavior of the all-solid secondary batterycorresponded to theoretical behavior.

In the graph of FIG. 11, a value of the discharge voltage against eachdischarge current density of the all-solid secondary battery is shownwith a symbol “◯”. According to this graph, it was confirmed that theall-solid secondary battery was discharged in the discharge voltagerange of 0.25 to 0.37 V within the discharge current density range inthe graph.

Comparative Example 2

In order to confirm an effect in the Example 3, an organic solvent(toluene) was added to the same electrolyte and electrode mixturematerials as prepared in the Example 3 so that the binders containedtherein were dissolved in the organic solvent to obtain variousslurries.

Next, the organic solvent was evaporated and removed from the slurriesto obtain solid matters, and then the solid matters were crushed using aplanet ball milling machine in the size of about 20 micrometers or less,to thereby obtain crushed matters.

Next, using these crushed matters as electrolyte and electrode mixturematerials, a conventional all-solid secondary battery was manufacturedin the same manner as in the Example 3.

Thereafter, a property of a discharge voltage against a dischargecurrent density of the thus obtained conventional all-solid secondarybattery was checked.

As the property of the discharge voltage against the discharge currentdensity, a terminal voltage of the conventional all-solid secondarybattery was checked at the moment when a discharge capacity thereofbecame equal to 10.0 mAh/gr against the used electrode active materialby discharging it at a current density of 0.1, 0.2 or 0.4 mAh/cm², afterit was charged up to 0.52 V at a current density of 0.1 mAh/cm² andcharge operation was stopped at the moment when an electrical currentbecame equal to 20 μA.

In the graph of FIG. 11, a value of the discharge voltage against eachdischarge current density of the conventional all-solid secondarybattery is shown with a symbol “Δ”. According to this graph, theterminal voltage thereof was about 0.31 V in the current density of 0.1mAh/cm², was about 0.25 V in the current density of 0.2 mAh/cm², and wasabout 0.15 V in the current density of 0.4 mAh/cm², respectively.

It was confirmed that the discharge property of the conventionalall-solid secondary battery manufactured in the Comparative Example 2was significantly lower than that of the all-solid secondary batterymanufactured in the Example 3.

What is claimed is:
 1. An electrochemical device, comprising: a pair ofelectrode layers; and a solid electrolyte layer provided between thepair of electrode layers, wherein at least one layer of the electrodelayers is composed of electrode active material particles each providinga function of the one layer, electrochemically inactive insulatingparticles and a binder which is composed of an organic polymer and bindsthe electrode active material particles and the electrochemicallyinactive insulating particles, wherein the solid electrolyte layercontains a silver-ion-conducting solid electrolyte, wherein the binderis carried on at least a part of a surface of each of theelectrochemically inactive insulating particles, wherein each of theelectrode layers is formed from a mixture material containing theelectrode active material particles and the electrochemically inactiveinsulating particles with the binder, and wherein the electrochemicallyinactive insulating particles are at least one of an alumina, a silicaand a zirconia.
 2. The electrochemical device as claimed in claim 1,wherein the organic polymer is at least one kind selected from the groupcomprising polyamide and polyimide as a major component thereof.
 3. Theelectrochemical device as claimed in claim 1, wherein an amount of thebinder to an amount of the mixture material is in the range of 0.5 to 20wt %.
 4. The electrochemical device as claimed in claim 1, wherein thesilver-ion-conducting solid electrolyte is an iodinated silver tungstate(Ag₆I₄WO₄).
 5. The electrochemical device as claimed in claim 1, whereinthe electrode active material particles composing at least one layer ofthe electrode layers contain a δ-type silver vanadate (δ-Ag_(0.7)V₂O₅).